You've got it ass about tit, Europeans can't create works based on US culture and sell it to them, but the US did just that to them 100 years ago but then forced crazy copyright on the rest of the world.

No-one can sell derivatives back to the US. The US can use elves, orcs, dwarves, vampires, werewolves, Repunzels, Thors, Lokis, fairy godmothers, Romeos, Juliets, etc. commercially all they want.

But we can't use Supermen, Wolverines, Mikey Mouses, etc. commercially.

I'm not saying it's a bad move from the US pov, but let's not claim it's done for the sake of artists, it's done for $$$ tax revenues and keeping US entertainment as a dominant export.

It's basically an extremely effective one way, heavily US favourable trade embargo that they've codified into international trade law.