[205guy]

I think there is a distinction here that needs to be made: copyright is about the marketplace, not actual ownership. If I drew a mouse cartoon and really liked it, and maybe just showed it to my kids every year, I could keep it secret and I (or my heirs) could own it forever. The public isn't owed any private works or any compensation for what could-have-been in the public domain.

But if I want to commercialize this art, then I need to release it into the marketplace. As soon as it is released, it can be copied (or there will eventually be a technology to copy it). Therefore, copyright is society's (and the government's) way of protecting my ability to profit while making my art public. In exchage for that protection, the US laws used to impose (there was not choice, other than secrecy or copyright) the release into the public domain after a certain time.

The issue is, marketplace protection (legislation, enforcement) costs money. The richness of public domain material seemed to justify the cost on society. If copyrights become perpertual, it would make sense to me that the ones who benefit should pay for it. Then again, they could argue that an open marketplace full of desireable content is valuable in and of itself (to both society and the economy).