I dont see how the competitiveness argument can still stand. I've been using both browsers for the better part of two decades now and chrome/chromium never was the better product. Sure it had slightly better devtools for a while but nowadays it is very difficult to argue either way. Performance was rubbish on both ends for years in a row, right now both seem to do fine. Firefox has sync, a significantly better product than whatever google comes up with every two years. So yeah, I think Mozilla has a good enough product to challenge chrome. What they don't have is comparable traffic to their site.

Oh and of course focus. Mozilla has lacked focus for almost a decade now with all the random products and initiatives they launch.

As someone who almost compulsively changes browsers every so often with the mistaken belief that "there's gotta be something better" and has swung by Firefox on multiple occasions, it has never offered me any compelling reason to stick with it beyond not being Chrome.

Zen came close, but also didn't stick.

Containers seemed nice at first but my personal usage of them devolved into an over abundance of containers to isolate everything from one another (my fault, though).

On the other hand, I've had various small nits here and there that always eventually push me back towards a chromium browser.

But hey, I'm a believer in not holding on to my decisions so long that they become assumptions, so off I go to install Firefox and give it a 4th whirl since 2010.