You know Dracula, the vampire that shows up everywhere? Back when Bram Stoker was alive, that was one aggressively-protected trademark. You couldn’t even bring up the guy without getting the legal hammer on you until his estate’s trademark protection expired.
Just think about it; In the 22nd century, everything you know right now? Pokémon, Spongebob, Twilight, Dragon Ball? As clearly-owned as they are now, that ****’s gonna’ be public domain the moment the copyright holder’s death hits its seventieth anniversary.
I kind of wish I could live long enough to see what kind of mythos will spawn and what people will do with the characters.