Because he has the potential to do Spider-Man numbers. Out of all the heroes in the DC world, Supes reaches the most broadest audience. He is no doubt THE most well known hero. The fact that his popularity isn't as good now, is not the point. That is the point where the filmmakers make it their responsibility to MAKE Supes relevant and likeable again. Which is why I was disappointed in what filmmakers did with the film. This was their chance to reinvent the character, much in the same vein as Batman got his dignity back, and literally dug himself out of the grave with Batman Begins. Instead, they opted to rehash a 2 decade old franchise. I mean geez, Supes has THE most coolest powers, and they barely showed how exciting it could be. That's partly why this film didn't get much success. There just wasn't much incentive to go see it, nothing in the trailers made it out to be a "must-see" like Spider-Man was. Note: Discussion Continued in "Superman Returns" Talkback, Part II (Spoilers).