I still think if copyright laws weren’t so oppressive, 50 years would be fair (And still a huge improvement from the current situation).
Maybe have it in tiers or something? First 10 years: full copyright - until 30: similar products allowed, but no blatant reproduction - until 50: reproduction allowed as long as it’s not for-profit - post 50: public domain?
Did those even change anything, actually? I just remember some statues being torn down and the police just doing their business as usual. They also need to be aimed at the correct targets for them to be effective.