Past international agreements are only as permanent as the people alive now agree they are. Yes this one will be very hard to change but that's just because there are many powerful interests that want to keep it this way.
Why?
The Beatles really wrote and performed Strawberry Fields.
Why are you entitled to it for gratis? It’s a taking for public benefit.
Ancient writings like Plato or Marcus Aurelius somehow feel different. But high-fidelity live recording feels like it shouldn’t go into the public domain.
It’s someone’s commercial work product