That would be difficult to implement, I think, notably when it comes to movies where creation is a collective effort and the copyrights belong more often than not to the investors. For instance, 20th Century Fox owns the copyright to the Simpson episodes, despite the fact the show is produced by Gracie Films to which Matt Groening licenses the use of his copyrighted characters.

Or you have the case of someone like George Lucas, whose copyrights are owned by his own corporation Lucasfilms, not by George Lucas as an individual. In his case, the deal with Fox is one of distribution. They release the SW movies under license from LFL.

And then in publishing you have the case of Robert Jordan. James Rigney didn't own his copyrights, his "Robert Jordan" corporation did, and had a publishing deal with Tor. Several other writers own their copyright on a personal basis, or their publishers own them.

A friend of mine develops characters. She's worked for Disney and Hannah-Barbera and co. Of course, by contract she owned strictly nothing morally or financially that she developped for them (it's worse, she couldn't develop anything on her own while in their employ, her contract specified all such work would by default belong to Disney unless they specifically release the copyrigh to her). In any case, to deal with all this (not only dealing with corporations in regard to your copyrights, but also to simplifly things with governments internationally), people like her don't own any copyrights on an individual basis, rather their create a corporation to manage them. They release their rights to the corporation and the corporation mandates them to manage the moral rights. It's all a paper thing.

The way things are done nowadays, I think it would be extremely difficult to differentiate legally between rights owned by the creators as individuals, and rights owned by corporations, or to justify that different rights are given to corporations than to the estates of individual creators, and again, it's very easy to transfer your personal copyrights to your corporation created to manage those rights.

The purpose of copyrights in the 21st century is much wider than the spirit of the original laws. They still ensure that being a creator can be a viable way to earn a living, but most of all they protect the investments in the entertainment industry. They even protect the customers to an extent, from being invaded by a plague of shabby releases mastered from god knows which source, making it difficult for the original studio to commercialize high quality versions, or justify investing hard cash in restoring or preserving works. For books in the public domain, there's already problems with all kind of shabby editions (I got caught with that a time or two, buying an omnibus for classics only to realize it was so cheap for very good reasons).

It's not only or even primarly their movies a company like Disney has sought to protect, it's the rights to Mickey Mouse, Gooffy, Donald Duck, their designs of Bambi, Cinderella and the whole she-bang. Had these characters fallen into the public domain, there would be nothing stopping publishers from churning out their own Disney albums and movies, opening Disney themed-parks, not to mention the Disney stuff wouldn't remain "family-friendly" for very long, as nothing would stop someone from making Mickey Mouse and Zombies, and mere days would pass after the characters are public domain until Disney porno cartoons appear. Without the new laws, the American entertainment industry would simply collapse. It produces every year some of the most expensive entertainment in the history of humanity, even novels can turn into massive investments nowadays.

I think culture has become way too much of an industry in modern times for the spirit behind the original copyright laws to still fully apply. As long as people want to see entertainment that cost over a hundred of millions of dollars to produce and to have a vast choice of productions released each year, and hundreds of TV channels, and video games derived from franchises that are very expensive to develop etc. they have to live with the fact these industries need to make a great deal of money to run. And it would be terribly hard to justify that the copyrights for a novel are dealt with differently than those of a movie and so on, especially that a works very often appear in multiple forms.

I don't buy the argument that copyrights stiffle creativity. There's always the possibility of buying the rights if a work could violate a copyright, and not only there's more than enough of that happening already, it's also bad enough that an estate can decide to release sequels to original works (most of which are fairly bad books) without us getting Lolita 2, and the expurged this and that.

Sure enough, I realize modern copyright would have also meant several works considered classics now would not have surfaced (starting with The Three Musketeers, for which Dumas picked liberally from an "autobiography" of D'Artagnan he knew well was in fact faux mémoires and a novel in disguise), but the thing is, it's no longer the 19th century.

And finally, behind this desire to see work enter the public domain and outrage at "rights stolen from the public" and stiffling of creativity, there's in fact a big deal of hypocrisy. What people really want are those works available for free. This phenomenon is getting worse and worse. First it's part of the music industry that's back to 19th century conditions, were independant artists find it more and more difficult to make a living because of piracy (artists would use to scrap a living selling 20 or 30 thousand copies now face 50,000 illegal downloads and 5000 sales - having to take day jobs to survive), more and more newspapers are vanishing because people seek their news from free sources and disregard the professional qualifications of real journalists - and the role the press plays in democracies be damned, it's getting more and more difficult to buy works in certain genre (ex: anime) in brick and mortar shops because illegal downloads have crashed the niche markets, and now with e-readers, it's book piracy that's becoming commonplace.