But the original constitutional copyright clause can be applied to a timeframe in which an artist can/should be paid for there work.
After all, artists got to eat.
And a good artist who can sell work should be capable of earning his money, which would encorage him/her to make more art.
Part of the reason that the guy who created Calvin and Hobbes quit was copyright violations on his work. He wasn't getting paid for his images, and got upset at not being able to control the images being used in ways he felt were distastful and wrong, so he quit producing.
Also, in regards to shakespeare, he used classic stories which were well known and so old that to find heirs to acknowledge would have been ludicrious. Same goes for him. We can't say who his heirs ARE.
At the sametime, we can now reliably research who's desended from whom, and I would say that intellectial property should become avalible to public domain once the original creators relations can no longer give a reasonable answer about how he/she would want their work used.
I mean, no one can say that shakespeare would not approve of the adaptation of Taming Of the Shrew done as a modern teen flick, but i'm pretty sure that j.d. Salinger and his heirs could give a pretty good account of why his work should not, and when they're all dead, whoever wants can play with it.
I think copyright is less about money as it is creative control. If I wrote a song, I can safely say that I would get nasty if someone wanted to use it to sell something I hate. Because its my expression, and I don't want to be associated with such things.
Thats what I think should be protected.
The how to do it part, I freely admit that I have no clue how to word it.