They both were just responding to similar market demands because end users didn't want to use RSS. Users want to use social media instead.
>This is a trillion-dollar ad company who has been actively destroying the open web for over a decade
Google has both done more for and invested more into progressing the open web than anyone else.
>The WHATWG aim is to turn the Web into an application delivery platform
This is what web developers want and browsers our reacting to the natural demands of developers, who are reacting to demands of users. It was an evolutionary process that got it to that state.
>but with their dependency on the Blink rendering engine, controlled by Google, they won't be able to do anything but cave
Blink is open source and modular. Maintaining a fork is much less effort than the alternative of maintaining a different browser engine.