99% of "you should switch to Firefox" articles focus on the speed of the browser. I used Firefox since it was beta till Edge came out when everyone around me was asking "why are you not using Chrome?", and the thing is, I never had much problem with the speed or the crashes, so I never felt the need to switch to Chrome. Until WP died and I bought an Android phone. Then I switched to Chrome so that I get perfect synchronization of my passwords, contacts, locations etc.

I think the reason why majority of people are using Chrome and Safari is not because of speed, it is because of synchronization, because of integration of ecosystem. IMO, if Mozilla provided a suit of paid services with built-in privacy like mail, contacts, maps, they might have a better chance that people would also use Firefox as their browser. Nowadays, Microsoft follows that approach; they provide Android launcher, Edge browser, mail, and pretty much every other service you need. I am actually considering to give Microsoft ecosystem on Android a try, at least their main income is not selling your data. But it would be even better if Mozilla launched a similar suite of services.