Given the current state of the Chrome family of browsers and the anti adblocker stance from Google, i'd think that alone would guarantee Firefox a steady user base.
Not sure how users cope with Chrome-based browsers and intrusive ads.
I've tried a few times to convince people in my life who would self describe as "bad with computers" to download an adblocker, but they usually find the friction too high. Adding extensions is unfamiliar for most, and even if it seems very basic for us, the non-tech people I know don't really want to deal with the risk of unknown unknowns from that, let alone switching to a healthier browser. (Perhaps reasonable since it feels like these days half the extensions on the Chrome Web Store are spyware or adware behind the scenes.)
I also suspect that those who lived through the days of frequent Windows errors and Chrome running out of memory all the time often expect software to fail in weird and unexpected ways, and a lot of people adopt a "don't fix it if it isn't broken" mindset.
Still, uBlock Lite and Brave browser are definitely easy wins and I'm glad to see more random people in my life using them than I would have expected. :)
That's just a wishful thinking. Too many ordinary users accept ads as inevitable annoyances and don't even know about the very existence of adblockers.