I feel like there's a missing step in the argument here. Yes Google's revenue comes from the web, yes Chromium being open source and paying for search deals are a hedge against anti trust, but why does it follow that they wouldn't want to dominate the browser space? They do, and it seems to be working quite well for them. But it feels more like a minimum effort hedge against antitrust then a demonstration of a healthy ecosystem.
Also, every time Chromium comes up you have people pointing to it like it's a counterpoint to their browser dominance. It's open source, so what's the issue? But the issue is that Chromium as a body decides whether commits make it into the browser and the decision making body is an invite only group of full time Google developers. So it is controlled by Google after all.
Not if you fork it.
But I think there are cases, such as Chromium where the "just fork it" response is unrealistic about the burden of maintaining a codebase or the ongoing relationship to new updates, or not having capacity to solve new problems or comply with new standards in Google-independent ways. Part of the problem of Chromium is that it's normalized a velocity of development and of codebase size in exactly the way you would if you were going for embrace-extend-extinguish.
And the foundational point is still true, Google controls commits to Chromium, so the core project itself is not ever going to be an organic manifestion of community desires for an egalitarian internet. It's going to be whatever helps consolidate Google's monopoly.
Plus all the Electron crap that gets shoved as "native".
4/5 top browsers by market share are there because they are preinstalled on millions of devices and none of them are terrible enough for an average person to look for an alternative.
Which I think is important as it relates to Mozilla. Because a lot of the arguments back and forth about Mozilla assume that change in browser adoption was about what features they did or didn't add. But I think that completely ignores powerful actors leveraging monopoly positions to drive users to their browsers, which is more important by several orders or magnitude. Any explanation of that history which leaves that part out is revisionist history in my opinion.