Firefox had the IT-sector with them. I think this does a lot for spreading the usage. Even just one IT-guy can probably give Firefox hundreds of users. Now, this is no longer the case and increasingly they have not only just been just as good or worse than chromium but they have gone out and actively angered a lot of their core user base with political things.
It is a fine browser, I haven't said anything else. It is the leadership that is bad. I would definitely be one of their strongest promoters if Brendan Eich were CEO.
But no, they kicked him out for a bs reason and employed a PC-dictator that fires most of the company and gives herself a promotion even though the usage is falling drastically.
Then they post shit like this:
https://blog.mozilla.org/en/mozilla/we-need-more-than-deplat...
https://book.mozillafestival.org/10-years-of-activism-commun...
and fund people like:
https://www.mozillapulse.org/profile/3116
If you consistently support specific political views it's not strange that the people who do not support these views will stop seeking them out and start recommending other browsers, how good Firefox may be doesn't really matter. They have turned Mozilla from a tech company to an activist company and now they will have to reap what they have sowed.