When Captain America entered the Marvel Cinematic Universe in Captain America: The First Avenger for Evans’ initial six-picture deal, the actor was not even sure if he wanted the films to be good, because he knew the amount of work and time commitment that would result from the success.
It’s always good to be in a film that succeeds, but the central concern here seems to be the fact that playing Cap could’ve easily ruled Evans’ life.
It requires years of commitment, and success only leads to more work.
Playing a part in a major superhero franchise is not a part time gig.