2D fighters in general are a dead genre, just like 2D platformers (on consoles, as a few still survive on the DS) and plenty of other dead genres.
It isn't that the games suck, just the majority of games have moved on. Brawl is the current exception for 2D fighters, but it could be argued that it isn't a 2D fighter, and that it is really a "brawler" since there are no complex moves, no health bars, and it is 4 player mayhem with items.