This is the point that company breakups start to make a lot of sense.
When Google can do something that every one of it's users hates and none of us can do anything about it, they perhaps have too much market power.
I don't think this is remotely the case. Quite a few tech-savvy people I know (some of them software developers) use Chrome and mostly don't care about whatever Google does with it. I mention "manifest v3" and get a blank stare. I talk about advertising and ad blockers, and most people don't care, with some of them not even using ad blockers.
We really live in a bubble, here on HN. Most people think of privacy as some abstract thing that they have little control over, and are mostly fine with that. And some are even also fine with government erosion of privacy, in the name of "save the children" style arguments, and of corporate erosion of privacy, in the name of getting free stuff in exchange for their personal information.
It's a sad state of affairs. If most people really did care strongly about these sorts of issues, then I think it would be baffling why we haven't seen more change here -- after all, Firefox is a perfectly viable alternative to Chrome that very few people use. But the lack of change is no surprise: most people don't care.
I don't use Firefox because it's slower than Chrome and because their behavior regarding limiting which extensions are available in phones, requiring signed extensions, Firefox Pocket, ads in new tab page, etc, does not exactly give me confidence that Mozilla truly has my interests in mind. In fact I bet they'll implement the nightmare DRM API once it's done swiftly and without complaint lest their money flow suffer.
If Mozilla ever decides to stop screwing around, clearly position themselves as an ally of the consumer, clearly express support for adblockers and put resources into making the browser faster and better and more customizable instead of whatever makes their CEO richer then I'll switch to Firefox even if it is a bit slower or has some flaws.
In the meantime uBlock works right now in Chrome which makes it usable, so since Chrome is the fastest right now, Chrome it is.
Firefox fails because there is no actual industry pressure to build a better browser. you simply can't sell a browser alone anymore: the free offerings have been good enough since the early 2000s.
Safari only needs to be good enough for iOS users to not abandon the platform entirely, and the ecosystem wants to push you into native apps anyway (Apple wants their IAP cut).
Chredge is, well, _there_, but basically just a minimum batteries included that maybe funnels some set of users into other Microsoft offerings, but it isn't the core product.
Chrome is, well, Chrome.
Firefox is comfortably supported by Google funding as an antitrust action shield. there's no real pressure for them to try and beat Chrome in market share because they're explicitly paid to be minority market share, and aren't really going to lose that share because they already have all of the "intentionally don't want to use Chrome" market. Mozilla faffs about making also-ran internet services (idk, whatever the heck that VPN offering was, etc.) because they fundamentally can't lose their main revenue stream so long as Google wants to avoid antitrust action, and have no real pressure to offer a competitive product.