United States vs. Google threaten independent browsers
blog.mozilla.org
blog.mozilla.org
I think the terrible administration from the previous CEO destroyed any chances of Firefox to remain capable of funding itself.
Most of their other attempts of monetization were often at odds with their own user base. As time passes, those attempts are less and less likely to work, as the user base gets smaller. The remaining users are likely only staying because of certain privacy-focused features (like tab Containers) or because uBlock Origin works best with Firefox. And I believe those people don't trust Mozilla to spend donated money wisely...
If anything, modern Firefox is a cool browser, and some interesting forks like Floorp do exist.
.. which, granted, is oversized, but this edit doesn't quite capture the meaning. Perhaps: Proposed remedies in US v. Google threaten role of independent browsers?