I'm using Firefox on Android - not sure what friction you're referring to here, but the lack of 'reload on pull down when scrolled to top' feature is seriously annoying for me.
Despite this, I stick with Firefox because I want to use it - I can imagine that the vast, vast majority of users who have no opinion on which browser they use simply don't/won't put up with this and just go back to the easier to use Chrome. It's little things like this that make all the difference.
In every other Android app there's no bound on how much scroll momentum you can build up; if you want to zoom to the bottom of a long page, you can keep flicking to go as fast as you want. Firefox mobile adds an obnoxious amount of extra friction that prevents you from going much faster than your finger moves, making scrolling feel like wading through water.
As an aside, I think iOS might have the same behavior, which could be the reason they're doing it, but it goes against the system standard and is completely unbearable for me.
I use Brave browser, which on desktop is a little slow, but on mobile is just a Chromium fork with some extra privacy features (including ad blocking). I'd certainly like to support Firefox in principle, but Brave is a good substitute.
Oh, good, I thought you were trading a bit of janky scrolling for an ad infested web :) I've never noticed the scrolling issue specific to Firefox but I feel like everything on Android has a few hiccups like that. I've always chalked it up to JVM garbage collection. I'd be surprised if Brave didn't have a few UI quirks too.
Edit: Just read your other reply, I thought you meant frame skips or something. I don't hit many long pages on mobile so I've never realized it did what you were describing. I wonder if they even know about it.
Seriously, it's the main reason I don't use Firefox.