Actually, for the masses, setting is pretty much completely irrelevant.
World of Warcraft is much worse in this area than EverQuest was, because of the influx of Warcraft 3 players. I was unfortunate enough to join my friends WoW guild made up entirely of WC3 junkies, and they couldnt even concieve of roleplaying or speaking in character. It was a strategy game to them, a way to kill things and take thier stuff, and nothing more. The majority of players out there are like that: they dont give a flying fig for the setting.
Get on WoW and ask the average gamer what the name of the world is... youll get a blank stare. Ask about any historical points of the setting... same thing.