Well, but doesn't Disney's copyright just apply to Disney's own instance? They can't claim copyright on other adaptations of Rapunzel, just their own and the specific style of character drawings and so on, right?
It's even more striking if you consider that those fairy tales and characters are the products of many, many retellings and adaptations throughout history. The Grimm brothers didn't write them; they just wrote down one version of a lot of them. In a real sense, Disney's modern retellings are just the latest iteration on this process.