why does every manufacturer make weak audio devices?

while true it is also not the whole story
digital source devices can generate signals at ideal levels for a DAC to create a proper waveform at the appropriate level (1v ptp I think) however they have much more capability than older analog-only devices in that they may also encode a limiter of sorts (basically saying the waveform is meant to be weak as it is a scene that is meant to only be half of the rest of the audio) the issue is not only weak speakers in bad setups with weak amplifiers (you say that the issue is only those thing which are tv/soundbar/andrio/ios) but also a lack of devices that properly level the loudest sound to the standard that line-level devices have used for decades (generated sound files tend to be only half(or less) of the intensity they should be to maximize line-level analog connections)
the issue is a lack of audio processing to maximize the starting intensity PRIOR to the TV amplifier and so weak signal in PLUS weak amplifiers PLUS bad speaker placement is the ENTIRE issue
my complaint here is the weak signal saved and then sent to the tv via the HDMI or the private listening
I had to max my headset which produces great audio with good sources just to hear the normal conversation of "the amazing spiderman" yet on my pc with the same netflix sources and headset (granted the digital bs the phone did to the data could be a factor) the volume only needed to be 60-80% to be tolerable
this proves that the roku device somehow reduced the audio waveform data in the digital space to have a 10bdm drop in intensity when most streaming devices should actually offer a 10dbm INCREASE in intensity to compensate for the limitations of modern flat-panel devices
so no this complaint IS to the CORRECT devices/company because my laptop would not have had DOUBLE the volume with otherwise IDENTICLE sources and devices
(maybe I should test the audio intensity by running the same test directly on the phone to eliminate that potential variable though bluetooth is digital and the phone was set to 100% so it shouldn't matter....)

edith no I am using a seperate device into a standard "dumb" flat panel tv via HDMI hence the improper physical headphone jack comment so I tested the audio stream generated by the roku brick using both private listening using a bluetooth headset to the roku app and then removed the roku software as a variable by listening directly from the netflix player in chrome
this basically created a 10DBm(roughly double the intensity) prior to the volume control of the device pushing data to the headset basically proving my point that digital sources can easily effect signal strength of an audio stream as the headset is not recieving analog from anywhere it gets a streamed audio "file" and then does the DAC part internally and so a weak "digital" source can easily be too weak for the later devices in the chain to boost high enough to be usable

DBDukes while true it is also true of the HDMI audio channel of my PC
but oddly my pc can reduce and even increase volume independently of the TV amplifier
which means that there factually exists a way to change the strength of a digital audio signal the directly relates to the volume the DAC and amplifier  will output, I actually have my PC tv set to 50% always and use the pc to change the volume for ease
and at no point did I claim my roku player with only a usb+wifi+hdmi+ir port has an analog output as I know it doesn't
I have been speaking of digital volume effects that are not listed within changelogs of firmware or in the settings pages of the device but must exist as the rest of the variables are unchanged(even the same content on the same streaming platform that has not changed during repeated watching on other devices but has changed only on roku)
so it doesn't matter if the roku player(roku tv's exist so yes some roku devices factually do have an amplifier)has an amplifier or not as it clearly has some form of digital-only reduction in audio amplitude data that must be originated on the only common thread that is independent of other variables that are unchanged
this means the only link that could be the root cause is something within the roku itself
now what is more plausible? all apps that have content decided to code their roku version and no other versions to have an identical(seemingly) reduction in content file volume, or roku implemented a firmware patch in the latest one they force on you that adds a global audio effect that offsets the value of the data points of the audio files it receives then sends over HDMI?
occam's razor says that it is roku doing this as the chances of independent companies or a massive and ridiculous conspiracy making it all happen within a margin of error to only roku versions of different streaming apps(not even all RISC, just the roku versions) is stupidly low
the earth is round, UFO's are mistakes, bigfoot is misidentification, ect, and roku has implemented a pointless and ultimately detrimental audio volume reduction no matter if it was intentional or not
or do you believe aliens have made a pizza earth that they sustain gravity with a technology that we have yet to even imagine, while simultaneously capturing or hacking our space probes to make it look like the earth is just another planet orbiting another star, and all the while making mistakes with their observations of us in a way not even the cultural scientists of star-trek would have made
are the aliens who make the earth look like something it isn't and failing to be competent in avoiding cultural contamination also making the sound waves selectively weaker only when I am on my roku? or perhaps are you uninformed on how digital audio devices work and don't know that volume can be reduced before it even reaches the DAC?

think about it, the literal only way to reduce sound pre-DAC is to apply an audio effect that directly offsets the amplitude of an audio waveform capture, this means that if the audio was properly recorded at peak efficiency(like all movie studios do) that if you have the volume set to a given level then basically all content will be equally loud.
in practice the exact point an audio engineer in a movie studio deems "clipping free" will vary but ultimately it will be within 50% of the levels of the loudest content on the market making a 30% offset in your tv volume control literally never needed outside of loud ambient environment or poor speaker placement reducing the amplitude of the audio wave that reaches your ears
but 20%->70%(as in my case) is literally intentionally ruining the experience as most humans will turn down the tv volume if it actually is causing hearing damage(which happens naturally with age anyway requiring a slow increase in volume just by getting older)
the only reason to add a volume reduction or cap setting is for children who actively make poor choices due to undermatured brains, anyone 18+ should never be forced to have volume reduced on all content ever
I actually use the windows audio enhancements that adjusts content to be roughly the same average loudness because sometimes content is naturally quiet and will make it heart-racing loud when windows makes a system sound
so yeah humans are pretty smart at controlling the volume based on the situation and NOT based on the manufacturer legal team saying something stupid like "if we make the maximum waveform size low enough nobody can sue us for damaging hearing when people turn up the volume because eventually it will reach a point they can't turn it up enough to get injured"
the ACTUAL solution is to make all audio endpoint devices(ie does the actual amplification not just fully digital audio signals) have a parental pin that lets you set a maximum output (full custom because no two setups are the same) that protects against silly kids and just let adults be stupid with nothing more than a warning popup that says "turning volume above this point is highly likely to be too loud for injury-free enjoyment, though we recognize your situation may be rare and actually need it louder so just be careful and realize you can't sue for injury if you press volume up again to confirm and dismiss this warning" or similar
but as my roku player literally only has an HDMI output I actually think I have the right to demand the audio reduction effect be removed from any non-speaker roku firmware as if it doesn't have an audio amplifier it cannot possibly damage hearing
and counterintuitively if only part of content creators and device makers make the stupid choice to reduce maximum digital file audio amplitude they actually increase risk to damage hearing as when content that is actually reduced ends and content that is not reduced (or even boosted like in commercials) it will suddenly and unintentionally be well over the safe threshold for hearing causing injury that is directly the fault of whoever thought reducing sound without options in a 100% digital domain was at all anything but a bad idea
so yeah this 100% digital effect that reduces only roku output audio data actively harms people as they turn up the volume to compensate(or buy external speakers that can get louder without quality reduction like I did) and when they change inputs(because that is a thing people do regularly as roku is not the only device a person will use) it suddenly blasts ears with painfully loud sound if they forget that roku is dum and way to weak audio
basically as I am a tech guy with experience in digital vs analog audio and what device ultimately controls the decibels the speaker can push to your ears and the importance of distance from the origin of the sound, I have come to the conclusion that there is only two possible reasons that my roku(factually the device that is reducing the ultimate content volume(though my pc did that too until I did some driver revert to undo an update that did the same thing to my pc)) is so low sound output
a: they are attempting to force regular purchases of new devices by coding a type of age based volume reduction(should actually be made into a criminal offense to code such a firmware forced obsolescence system)
b: the people forcing this addition in have no actual understanding of how sound waves propagate or how actual real-world audio setups tend to get used
this means either they are maliciously adding this reduction to enforce sales that otherwise have no reason to exist(not sure why they would do this as they can't be making much margins on the smaller roku player devices vs the content app rentals and such) or they are just allowing an uninformed person to make decisions they have no knowledge to be trusted to make such decisions
either way I expect that if they are not wishing to force everyone with a roku to buy a fire-tv or android-tv device instead and likely not use the roku app service anymore removing all income for roku, they will slowly revert the audio reduction in subsequent firmware updates until it is 100% gone
now this is assuming they care at all about feedback as a method of ensuring their income doesn't dry up from a flaw they had no idea was causing users to switch
and that they actually care about long-term profits
but there are only two facts I know of that make this a known bug that is actively risking the health and enjoyment of many users
1: this device is causing a noticeable reduction in maximum sound amplitude by messing with the digital audio stream in some way
2: reducing volume on a digital file that is never the only source of audio will directly lead to an increasing audio amplitude gap between unaffected content and affected content which if not in the perfect situations can lead to audio outputs the briefly spike well beyond hearing damage risk due to the natural compensation humans will do when they can't hear the roku content because of the volume reduction effect
so there is but 1 sensible choice and one poor choice to this situation for both the end user and the company causing the issue
roku can make the good choice and remove the effect entirely and rely on the natural adaptation of humans with a volume control and parents with a parental lockout chip
roku can make the bad choice and continue or even increase this effect causing damaged hearing and eventually abandoned devices that will not ever be replaced and eventually remove all revenue as some future smart tv devices will start to just not include the roku app because all users will begin to complain about it never being loud enough
for end users your choice depends on the choice of roku updates
if roku makes the good choice you sticking with them is good, otherwise it is bad
if roku makes the bad choice then your choice is flipped 
but ultimately the only good outcome for all involved including unintentional side effects caused by this feature or bug being included in roku firmware is for it to be removed from future firmware

I would be ok with them realizing that it has gone too far to flip off in one go, that would cause the damage they started risking by going so far in the first place, but any further reduction in audio intensity or the continuation of the current factual reduction(I literally tested the roku vs another HDMI device and it does have a ridiculously weak audio output that doesn't even save power or reduce device heating as it is all digital until it hits the TV and may even increase heat and power draw by the addition of a useless audio processing effect) would be a really bad idea that may soon irreparably ruin their brand and profits even if it takes years for them to feel the pain of their bad choices

and no it is 100% the roku device causing the issue as my tv literally never gets firmware updates as it is not smart and I don't regularly download firmware files and flash my TV's and as no other device is in the chain that is capable of connecting to the internet and is actually powered up, let alone connected to the hdmi of my tv which should not be able to push firmware to the tv, in fact I haven't had another device that has an internet connection attached to that tv for years, even my wii and playstation 2 have not had internet in ages(the wii hates my wifi as they are always picky) and my playstation 2 is almost never powered on with the network cable attached and doing anything that interfaces with the network card and my steam link has been unpowered since even before the audio started changing
I have eliminated all reasons the audio would be reduced besides intentional firmware tweaks on a roku device that has no analog components other than the resistor divider inside it for feedback to the switch mode power system and similar
remove the hidden firmware audio effect, replace it with a visible and configurable effect, or have me learn coding just to reverse engineer your firmware and remove it myself risking bad actors using my desperate efforts to push malware into your otherwise decently secure streaming devices
your choice roku, don't **bleep** it up