Earlier quoted context omitted.
This! I'd be very happy with a fixed, lower tier of web standard that is easy to implement against. It should contain enough standards to build attractive, solid (eg) online banking interfaces, blogs and news sites, commenting etc. In other words, a minimum for media consumption, rather than apps.
Building a browser that supported only AMP would be one way to do this and have a significant number of pages you could handle. (Disclosure: I work for Google on AMP ads. I also know how much people here dislike AMP, so this is not entirely serious.)
I'd quite like an RSS+reader view browser. At a guess, RSS+reader view+AMP could cover pretty substantial amounts of existing content.