- HTML is worked on by WHATWG
- CSS is worked on by CSSWG
- JavaScript is worked on by TC39
And IE wasn't killed by features moving too fast, Microsoft made Edge browser and still does. Mozilla hasn't been killed by Google or competition, it's been kept alive in large part by Google (I think in some years as much as 90% or more of its total income coming from Google) so they get hundreds of millions—the problem at Mozilla is bad management for the last decade.
I'm not sure how well this vision represents reality as it already is today.