If we were talking about an ordinary creation, like a physical object, then I'd agree with you.

Creative works follow different rules though. The most successful ones become part of our shared culture and they permanently infect our brains. They become part of our jokes and our metaphors. You can't opt-out.

The most extreme example is Happy Birthday. Because of copyright, you can't legally take a recording of your child's special day and share it with others. It's a ridiculous situation, especially for such a basic song.

It's fine for the author to reap the rewards of their creation, but there needs to be some limit. 50 or so years is not asking too much.