Majority of users are on mobile now, and Firefox mobile sucks ass. I cannot bring myself to use it. Simple things like clicking the home button should take you to homepage, but Firefox opens a new tab. It's so stupid.
I don't even have a Home button that I can see, I must have turned it off in settings? I describe my tab count using scientific notation, though, so I'd be a "new tab" guy, anyway. But I'd also be a proponent of it being configurable.