Sure, but Google has no control over any forks of Chromium. They can't control Edge, or Brave, or Vivaldi, or a hypothetical Mozilla fork. And if those other forks want, they can collaborate together to maintain any features they want to have that Google themselves don't want.
Like, yeah, more funding for Firefox would be the ideal case. But that's not something Mozilla really has the ability to effect. They can choose what engine they're using. And using Chromium would allow them to essentially "steal" the work Google has put in, while not preventing them from changing stuff that they don't like. In fact, in some respects it would help them even with that stuff they don't like from Google, since they can pool resources with other privacy-forward browsers like Vivaldi and Brave. I honestly see it as win-win.