The real problem is that firefox is tier 2 support or not even. It's a small percent of users so it's a cost/benefit for these businesses.
A recent issue I had was buying tickets from air india. You can't with firefox... it'll hang at a certain point. Switch to chrome... works perfectly.
The web is dead. It's basically client/server nowadays. Firefox is still my main browser, but I keep chrome/chromium around when I need it.
