Google has already given Chrome an unfair advantage by leveraging their other services. I suspect the browser market is an unstable system where absent outside intervention Chrome’s 65% market share naturally becomes 100%.

Chrome is such a complicated piece of software that the “forks” are highly dependent on Google and when Google unilaterally makes decisions they have to follow suit. Brendan Eich explains that Brave will continue to support Manifest V2 as long as Google doesn’t remove the underlying code paths: https://twitter.com/BrendanEich/status/1534893414579249152

I think a lot of people don’t appreciate how delicate the balance of web standards is right now. We have it so good (three high-quality implementations of an open spec) and I’m not willing to throw that away just to run Chrome on my iPhone.