Rumors of Firefox's death have been circling for at least 15 years now... somehow it's kept going despite odd incentives and bad corporate decisions.
It was the alternative to IE6, the first rays of dawn bringing hope to to a desolate, war-torn funereal valley of culpable corporate complacence.
Hatred for IE6 drove people to Firefox more than anything else - IE was horrible. Firefox users crowdfunded a two-page ad in the New York Times, mostly to get people to move off of IE6.