As pointed out above, individual use of Firefox doesn’t really do that much. Especially when Firefox already doesn’t work properly for some sites. Plus, lots of people (myself included) need to use Chrome for work. This shit sucks.
Have you used Firefox recently? I haven’t had even one instance of a website not working simply because of Firefox.
I use it daily. It’s my default browser, but it ain’t perfect. Most recently, it was an interactive map for Diablo IV that would never work on Firefox. After an update it started working, but that’s just the most recent example.