User blog comment:Scgriffin94/Death in Marvel movies/@comment-1895174-20140328233137

Because movies are a contained medium. They're supposed to tell one complete story in a fairly short amount of time; wrap up as many loose ends as possible in around two hours. Killing off the bad guy is an easy way to resolve the central conflict and leave closed the possibility of him returning in a future installment. Most of the time, that's for the best. We don't want our movies to be a retread of an earlier installment. Look at what's happened with Lex and the Superman movies. The common complaint with them is that Lex is always the bad guy, and that's not far off. Of the six Superman movies produced before the property rebooted with Man of Steel, four of them feature Lex as a primary or secondary antagonist. We got tired of seeing Lex do the same hair-brained stuff in each movie.

Or, if you want a more contemporary example, look the the X-Men movies. It took us 13 years and six movies to get a movie where Magneto or Stryker wasn't spouting off mutant-superiority or mutant-bashing (respectively, of course) rhetoric. And we're just now getting Sentinels, and we'll have to wait another two years for Apocalypse. Meanwhile, there's no sign of Sinister, no Friends of Humanity, no Genosha, not even Mojo or Shi'ar if FOX has any intention on taking these movies to weird places. This franchise hasn't barely evolved in more than a decade. Maybe leaving Magneto and Stryker behind and moving on to bigger things would have sped that up.