Why are all of the great titles coming out now sequels?

You forgot to list Fable III, bro. Anyway, I think it has more to do with marketing and commercial purposes. Like what Disney does: did Mulan really need a sequel? Did Cinderella who lived "happily ever after" after the first movie really need two more movies? I think it's that companies know they can play on people's nostalgic feelings and release/remake/continue something people already liked. The Smash Bros series since the n64 was pretty great but now Nintendo can and has milked a lot of profit by "remaking" (term loosely used) a game in same the flavor for each of their new console because they know it will be popular. Whatever console Nintendo dishes out after the wii is bound to have a new Smash Bros game to come with it. Coming out with a completely new game is refreshing but there's also a chance it might not be a hit.