firefox was always destined to die - i've had it installed since it was phoenix, and nameless before that (nia 2) - but firefox was always going to go the same way as netscape and mozilla in general.
mo: start from scratch and build a really streamlined, high speed browser for the masses.
5+ years later: the browser starts to slow due to the amount of bloat added (by demand)
nearly a decade later: the browser is a clunky mess of high editable code badly in need of a rewrite.
x amount of time later: look internet! we're gonna release a new, streamlined browser for YOU, because YOU asked for it.
and so it goes on.
i used to use firefox a lot for general browsing - opera has been my main browser since the late 90's, but firefox was a decent alternative, and using some of the great extensions put it ahead of the competition for a good while, imo; but it's been on the slide for a while now, and no doubt it will be reincarnated under a new guise during the next couple of years.
i still have firefox installed on my linux and windows boxes as the extensions are handy and mantra can be really useful, but i'm using opera and iron for my main browsing needs now...
as far as the ff os goes, does anyone really give a damn..?