Looking Forward To "Superman Returns?" How About Its Sequel?

Sequels are already in the works for Superman Returns and Batman Begins, even though Superman hasn't even begun to fly yet. (It opens this summer.) Both will tentatively feature the same directors, Bryan Singer and Christopher Nolan. No surprise there -- they don't launch franchises without plans for at least two sequels. What does suprise me is the little tidbit that the Warner Bros. movies were made with Legendary Pictures -- the studio and the shingle split the budget (which was massive) and will split the profits. To me, the only reason to split the costs is when you can't get all the rights or the movie is wildly expensive and uncertain, so you'd rather limit your downside. But with movies as presold as Batman and Superman, if you don't feel confident enough to make it on your own, whatever the cost, you shouldn't make it at all. If you do feel confident, why give up half the profits?