I'd rather see Mozilla reformed rather than sink. It's the only non Chromium browser that still exists, isn't such a memory hog, and has good extensibility.
It ultimately depends on the "how" though, like if Mozilla were to act selfishly, they could get aggressive with the trademark and kill the brand recognition of a fork, possibly even requiring interface changes. Alternatively on the other end of the spectrum, if they simply passed Firefox in it's entirety to the community, it could possibly end up in a Thunderbird situation where it experiences a revival without a fork being necessary.
Absent Googles funding, I think the best case scenario would be it's top leadership leaving as the budget stops being capable of sustaining the salaries critical for "supporting their families" and Mozilla gradually transitions into the non-profit it was always meant to be, soliciting donations exclusively for browser development. All while free from any concerns about pissing of Google and losing their main source of funding.
Then you've got Servo and Ladybird, which are coming along. Truth is, the reason its so hard to make a browser is because they have to support all this insane cruft, which I believe is by design so as to prevent new entrants to the browser market. The only way to fix the problem is to drop support for all that crap.
Mozilla is entirely captured by Google. They exist to protect google from antitrust law, they collude with google to damage the web, they're not a true alternative. They're complicit in their own downfall because they're paid to comply. Honestly what Mozilla is doing is more off putting to me than what google is doing.
Touche, but it's only available one one platform and aren't the both descended from WebKit?
https://www.xda-developers.com/safari-for-windows-editorial/