Until Google puts their hands in it, Firefox or any other browser will probably never be as mainstream as they should.
There is just too few people knowing it even exists!
I think Google is one of the very few companies to be widely known enough to get people to think that Explorer is not the only browser there is.
Many people just don't even know what a "browser" is!! They just go "uhm... the internet is Explorer... u know, the big blue e thing...?"
They say "click on the internet" pointing at the "e" of explorer. And all because the thing is imposed into people when they first put their hands on a PC. Much like WMP.
Wouldn't mind if they weren't complete pieces of crap!!!
Kinda like "playing videogames" used to be "playing Nintendo" and today it's "playing Playstation".
The internet for those people is Explorer and that's that.