Firefox in absolute numbers may seem irrelevant, but in other contexts it's actually the best or only browser by far. A couple of examples just in my usage:
Running Fedora in a VM on my Mac mini. Firefox seems to perform much better/less crashy than other browsers.
Brought an old MacBook Pro with drive issues out of mothballs and reinstalled OS X up to Sierra. Got a semi-recent build of Firefox working on it just fine and the computer is now essentially as usable as a Chromebook.
And that's the thing about the web. You can't just point at numbers and say "well, most users are on A, B, and C, so we'll only support those." Some of those users may actually be multi-platform and will get pretty upset when your product is broken in 1 or 2 out of 4 or 5 places they try to use it.
Running Fedora in a VM on my Mac mini. Firefox seems to perform much better/less crashy than other browsers.
Brought an old MacBook Pro with drive issues out of mothballs and reinstalled OS X up to Sierra. Got a semi-recent build of Firefox working on it just fine and the computer is now essentially as usable as a Chromebook.
And that's the thing about the web. You can't just point at numbers and say "well, most users are on A, B, and C, so we'll only support those." Some of those users may actually be multi-platform and will get pretty upset when your product is broken in 1 or 2 out of 4 or 5 places they try to use it.