In a no copyright environment you'd have everyone, literally everyone, writing folklore, ideas, stories, coming up with their own twists to the lore, their own takes. Historic mythology didn't develop from one writer it developed through people telling stories and adding bits or their own twists.

The good ones caught on and were adapted by others, the bad ones did not. The overall story and the "popular" mythology of the character/tale would form this way collectively. But it would still be a bunch of individual storytellers doing it.

The property model is what prevents this occurring collectively in a more natural human fashion.