Twitch app on Roku

This comes up every once in a while and you'll always see the same answer - it's up to Twitch to create a Roku app.  Roku can't and won't do it for them.

there was one. Twitch is owned by Amazon. Amazon pulled the official Twitch app from Roku in 2017 as a buisness decision (I believe this much is proven fact as far as I can tell). it was also buggy and lacked updates by Amazon. 

there are often third party unofficial apps but those come and go and only ever have really limited functionality (as you can't sign in). (search in streaming store for various ones that currently exist. prepare to be disappointed unless they somehow fit your needs.. then SCORE!! and congrats)

It's mainly Twitch tho it looks like as it's similar to official twitch being absent from some other platforms but could be a lack of ability to come to agreement between companies, I am unsure.. there's a lot of potentially likely speculation as to why (roku and fire tv are competitors, etc)