And we're running out of those. LotR, Star Wars, Star Trek, seem like three big ones that had a lot of potential but just didn't cut it in the end. Original IPs can be just as awesome, but generating them (then generating fans to care about them) is way, way harder than drawing in people already predisposed to like things like lightsabers or elves.
I think the industry might draw the wrong conclusions from Tortantic and never sponsor a AAA MMO again . . . with the one exception of Titan. The future of high quality, high population MMOs kinda rests on Titan's shoulders - and I'm not very optimistic about how Blizzard is going to handle that one