Not only do long copyright terms not incent creativity, they actually diminish the motive for creative people. Once they get one well-paying license attributed to their ownership, they can live off of it the rest of their lives -- and not only the creator/rightsholder, but generally multiple generations of his progeny. In a fair-but-reasonable world of copyright terms, one would be free to hold a monopoly on his creation for several years and make plenty of money off of it (in some cases, more money than anyone could need), but if a dependence on the government-granted monopoly was still important to the rightsholder after 10-15 years, he would be incentivized to create new stuff. His progeny would also be so incentivized, instead of living off their forefathers' work for 3+ generations and never needing to contribute anything themselves. This also means that works can enter the public domain while they're still relevant; with reasonable copyright terms, Star Wars would be entering the public domain. There are plenty of people who can remember Star Wars' opening night ... how many still living can remember and appreciate the opening of The Seven-Year Itch?