1) You seem to think nothing can be fucked up as long as it's still better than others. That's ridiculous.
2) Even accepting a major breaking change was necessary, it was absolutely not necessary to limit functionality -- again not being worse than Google doesn't mean they didn't fuck something up.
3) Defaults matter and the time, money, and effort spent on those was clearly detrimental to the core browser.
4) But constantly shrinking the margin by which they're better has cratered their market share and created a real danger of ceasing to exist as a meaningful alternative at all.
Good luck trying to "no stupid user, shut up and accept that our choices are better and we know better than you about what you need in a browser, plus Chrome bad!" Firefox back to the top. You angling for a job at Mozilla?