Here's something I've been thinking about that I don't have time to beat to death right now:
Corporate superhero comics and studio age films relate to one another in very similar ways. What am I talking about? Well, take the Warner Brothers career of James Cagney for instance. Cagney was a "star", not an actor. People usually make this distinction in order to establish the superiority of the latter. But let's forget about value judgements for a second (or, preferably, forever!). Cagney's "persona" isn't so different from a costume and powers. It's a constant in the films, from The Public Enemy to Yankee Doodle Dandy. Sure, they "retconned" gangster-Cagney into a more lawful version of himself in G Men, once the Legion of Decency turned on the heat in 1934, but he's always the same guy, even when he's playing a tapdancer. Various directors and screenwriters have their fun with this persona, but they're all riffing on the "origin story" that William Wellman and Cagney himself gave us in 1931.
Different aspects of the protean character are emphasized in order to serve the story, and our full appreciation of these variations is dependent upon our knowledge of what has come before. I can't imagine anyone loving The Strawberry Blonde as much as I do, for instance, unless they grasp the full significance of the fact that, in this film, Cagney's romanticism, which is always there, although usually in the background, is so much in the ascendant that it actually causes him to lose every fistfight and get taken in by confidence schemes left and right. He still thinks he's "Cagney"--a guy who always gets the better of his opponents, no matter how much of a physical or social advantage they possess over him--and so do we, but here that cockiness is misplaced, because all of his energy is channelled into this hopeless lifelong obsession with Rita Hayworth. And that makes every reverse he suffers all the more poignant!
And it's not just the stars of course. Just about every Cagney film has a role for Alan Hale, Frank McHugh, George Tobias, Allen Jenkins, Bogart as arch-enemy etc... They're just like the supporting cast in a Spider-Man comic... They can be bent to different uses, by different storytellers, and you can perform a similar historiographical reading of the variations in their roles.