Not an Android user, but I can speculate about reasons.

Most people don't install browsers. They barely know what a browser is. So they use the one pushed to them, or the one familiar with. In the case of Android, I believe Google Chrome is typically shipped as the default browser.

And as it works fine, there's no incentive to install anything else. I doubt young/new internet users would even know about Firefox.

If not set as default browser already, Google pushes it from widely popular services like Youtube.

Bottom line, Google can reach billions of people, Mozilla none.

Please remember this: people do NOT chose browsers, compare them, pick their favorite. They do none of these things. It's a collective illusion by us tech folks.

I still do for ideological reasons, but I used to recommend it -- now I can't really since their rewrite of it last year -- every single time I tab out or briefly switch apps it reloads the page: https://github.com/mozilla-mobile/fenix/issues/19291

I've lost days of my life waiting for these reloads. It's ashame because it used to reliably out-perform chrome on my phone.

I used to use Firefox on Android but had to stop because of this issue. Too many times filling out a form, grabbing a password from a password manager, and returning to find the form blanked. When it's resolved I'll go back and try again.

https://github.com/mozilla-mobile/fenix/issues/12731

I did until they broke all addons without warning a year or two ago. Completely unacceptable in a consumer app.

I briefly used it on Android. The scrolling momentum was all wonky, totally different from the rest of the system, and using it was unbearably unpleasant for me. I resorted to digging into developer menus and manually tweaking parameters, trying to get it to feel remotely good, and eventually I gave up.

I don't understand why they would make it so, but that's the sole reason I stopped using it, despite being otherwise willing to go out of my way to support them

With great sadness I've started switching to Vivaldi, which also has ad blocking on Android.

The combination of the big Android update and now the proton UI on desktop has finally pushed me over the edge. I've been a loyal Firefox defender since the mid-2000s but I don't understand what Mozilla are doing any more.

To add to the comments not mentioned any UX reasons, I wanted to use Firefox on my phone as I do on my desktop and laptop but when using it I disliked the tab organisation compared to Chrome, and that's pretty much all I need the Web browser to be good for on my phone, where I'll often have up to 100 tabs open. Maybe it's changed now but Firefox had an impractical 3D scroll through tabs showing only the top IIRC, whereas Chrome has a much more practical grid of page previews that allowed for easy navigation. It also now allows one to group tabs very nicely.

I hope Firefox has changed, or that there's a setting hidden away somewhere for these.

I'm wondering as well. Back when I used Android, I did use FF all the time, with uBO saving big time on traffic. Now on the iPhone I use Safari because I think it has power efficiency nailed, but maybe I should use FF for iOS instead?

Because Chrome comes standard on Android and Firefox has little marketing.

ad blocking is the #1 reason I open FF on mobile.

The lead developer has open contempt for the users, for one thing. Also, anyone with a few neurons to rub together can tell the UI is absolutely terrible from a functional perspective. Form over function, on a browser whose target demographic was supposed to be power users (long ago, in the misty past).