You can feel comic-book movies struggling to grow up, slowly and awkwardly. Problem is, they don’t really want to — and it’s not at all clear that growing up is good for business. Comic books and comic-book movies are a consummately American narrative form. Americanism, meaning a worldview or state of mind that permeates much of the human population, far beyond the borders of the United States, is built on the proposition that you never have to grow up.