I don't think Firefox will rise from the ashes like phoenix. There could be a temporary rise among the geek communities but even that won't be enough and won't last long. Brave probably has more potential than Firefox to increase its user base due to MV3 because of its built-in adblocking capabilities which Firefox lacks.
I'm similar, I have screens in front of me during the working day, when I've escaped from that environment I tend to avoid using screens if I can for browsing purposes, quick checks for information etc excepted. I still quite like taking in what is around me rather than what is shown on small screens from the real and virtual worlds.
Not only a chance, but rather a great probability that most users simply don't care about any of this. I've been a member of this forum for 7 years and my wife could give a rat's ass about privacy on her phone, iPad or anywhere else. I gave up trying persuasion long ago.
Its not just trying to convince people to use a more privacy/security-focussed browser, its security and privacy online that I fail to convince people that are close to me to try using. Eyebrows rise when I start talking about this. But, I won't let them convince me to go over to the other side!
That's what made me drop Firefox as my daily driver. Dishwasher died, went to purchase a new one and the website wouldn't render properly in Firefox, so I was forced to use Edge (which I had not long dropped too, ironically).
I still use Firefox as a secondary browser, to compartmentalize the stuff I want to keep away from prying eyes, but for my primary browser, I want one that lets me browse uninterrupted. Firefox, sadly, doesn't do that.
Personally think Firefox will do just fine. Remember when Internet Explorer was the infallible king of browsers? I never thought it would be up-ended by Firefox and Chrome back in the late 00s the way it did. All it takes is one big misstep and people start migrating. The biggest competitor of Chromium is Safari/WebKit anyway. People spend way more time browsing on their phones than on their desktops now.
Back to Internet Explorer, it took a long time for people coming from IE get used to Chrome/Firefox but they eventually did. Once people get tired of Google's games they will make the move to something better.
Yeah, an optimist! I do hope you're right on FF surviving, Firefox will be 20 this year, I've been using it for most of that time, or derivatives of it. Currently Librewolf is my primary browser with Firefox second in the lineup. I've tried many of the better known alternatives, Edge and Chrome are evil, Brave, Vivaldi have their plus and negative points IMO, I've never really hit it off with either. I have others like Ungoogled Chromium that I want to like but never quite reach that point. Firefox may have some issues, it may not be the fastest, but I must be slowing down if that is the case as I can't always keep up with it. I'm sticking with it despite some of the dubious 'innovations' and policy decisions.