You ever think about we kinda have copyrighted characters that are sorta treated like public domain characters? Characters that have such legacies that they have been put into the cultural fabric but without a solid lore so people frequently experiment. Like with Scooby-Doo, most mainstream superheroes, and things where people "know" it's a thing but haven't actually consumed anything from it directly so they just have an "idea" on what it is.
Like, it seems every other adaptation is a "unique take" on these things. It's like they're treated like they're public domain but some CEO has to approve it. I feel like, when focusing on derivative works, being in the public domain will help these characters the most. Plus, more experimentation can take place since there isn't as much pressure as being the only new entry in the franchise. Would Shrek be as loved if it had to be an Officially Licensed "FairyTaleCo" product and was the only Fairy Tale media in 2001?