Iron Man especially never has to stop. First, he's a suit and doesn't even need to have an actor, just a stuntman, Iron Man 3 proves that on screen. So if Iron Man needs to say something have RJD talk into a tape recorder and then loop it into the movie. How physically demanding is it to show his face in the helmet? And even without the face shots, the suit is Iron Man. Even Spider Man or Hulk can show up without even getting an actor. The others can have stunt doubles in costumes, although that's a little harder for Black Widow because she doesn't have any mask at all. These characters can and should last forever. That's not to say they have to be the sole focus of all movies or any, they can be the characters in the part toward the begining or end or just mentioned in passing, but they can always be there. With how good Chris Evans looked as skinny Steve Rogers, I don't think anyone can "not be replaced"
Last edited: