> would air my grievances when the Mozilla does something I disagree with more than I would when Google does.

Mozilla doesn't care about your grievances. It collects lots of telemetry about you by default, and has recently officially removed the obligation not to sell your personal data to third parties etc. It also plans to "introduce AI" into its browser.

> And I would expect that most Firefox users are of the kind who have strong opinions about how their computers work.

On the contrary. Those people have moved on, or are in the process of moving on, from Firefox itself to more privacy-minded forks. Like Palemoon, LibreWolf and maybe Mullvard.