Copyright can be debateable even in the visual arts. Galen Rowell, the nature photographer, and several other published photographers took Costco to court over use of their images in Costco advertising without attribution or payment. Costco's defense, as I understand it, was that having purchased photographic prints from the artists, they were entitled to do what they wanted with "their" copy of the artists' work - including reproduction of it. I realize this is probably an oversimplification of the case, but it's all I understood from Rowell's description of it in Outdoor Photographer a couple years ago. I don't know how, or if, the case was decided.

The music industry has many examples of creators who no longer own the rights to their own creations - Michael Jackson buying the copyrights for much of The Beatles' work and selling it for use in advertisements is one example, and John Fogarty being legally enjoined not to play any of the music HE wrote for Creedance Clearwater Revival because he sold the rights to the record company is another. Extending a copyright in these instances gives no reward to the original creators, but a lot to the scavengers who would like to see the payback on their investments prolonged.

There needs to be some mechanism for giving legal protection and renumeration to the creators of "Art", whether written, visual or musical, but right now the copyright system seems to be heavily biased toward corporations and away from the actual artists themselves...