It is undeniably happening. One benefit is you ship the same UI for all screens. For several billion people, the power user features mostly serve to shoot them

It is undeniably happening. One benefit is you ship the same UI for all screens. For several billion people, the power user features mostly serve to shoot themselves in the foot, and then they blame the browser manufacturer. On their phone the software either works, or it does not without explanation, in which case you need an expert, and for most people this is perceived as an improvement. Desktop software development is pushed in the same direction. Fewer people complain, and its a lot simpler than doing fine grained settings and informative error messages.