Marvel seems like it'd be even worse since A) the storylines all intertwine, so you feel like you have "homework" to watch before seeing the latest one, and B) they're all pretty much superhero movies.

With Star Wars, creators can ignore the tired Skywalker storyline, plus there's no genre expectations tying creators down (IMO sci-fi is not a genre so much as a meta-genre or motif). At least in theory--they've been pretty reluctant to spread their wings until recently.