This article is extremely misleading in two ways:
1) The reality is that effectively no consumers even tinker with their TV's settings to turn on Movie mode and turn off all of the garbage image "enhancement" settings, let alone spend 100s of dollars to calibrate or have their sets calibrated. If Dolby Vision does this automatically then that's a huge win for consumers.
2) It ignores the biggest difference between static HDR standards like HDR10, and dynamic standards like Dolby Vision, HDR10+, and Advanced HDR. HDR10 uses a static setting for the entire playback of a video that will at best be a compromise for most of the video; while Dolby Vision, and it's competitors, constantly vary the display to optimize the picture quality at any given moment, even down to a frame by frame basis.
I'll bet that the real reason that Roku doesn't provide dynamic HDR is that they've set the price of most of their products down to such a low point, so as to maximize their market share, that they can't afford to license Dolby Vision or even implement the open source HDR10+ standard. In effect they're bargaining on their customers' ignorance. And it's probably the right decision since most consumers won't even notice that their Netflix or Amazon video wasn't streaming in 4K, let alone that the color was a little less than the best that it could be.