Humans have been freely copying each other for millions of years.

False. Master artisans have been keeping their knowledge secret in order to maintain a competitive advantage, only eventually passing their knowledge to the most advanced of their apprentices. Tons of knowledge has been lost over the millenia to Masters taking their knowledge with them. Temporary monopolies (Patents) and Copyright protections, in exchange for making the knowledge public, is what has enabled its exponential expansion.

Keyword being “temporary”. We have Disney to thank for turning Copyright’s temporariness into a mockery of itself.