Is there a question in there besides the subject? Yes, FF has been dead for quite some time now.
The crossover point with Chrome was Nov 2011 when it held 23.5% market share.
The crossover point with Safari was June 2014 when it held 13.78% market share.
The crossover point with IE was Sep 2015 when it held 9.83% market share.
It's now at 4.1% market share.
The only 2 viable browsers today are Safari and Chrome. That's why IE became Edge, based on Chromium.
https://gs.statcounter.com/browser-market-share#monthly-201002-202008