Hell, WoW has twice as many active subscribers as both the 360 and the PS3's (non-combined) total user base IIRC.
Far from twice as many... maybe about equal to the 360 total installed base. It's tricky to count, because of the supposed millions 360 shipped back for refurbishing, and the huge numbers of WoW in China, which, IIRC, pay about 7 times less than Western subscribers...