Er, no. The reason why physical property can exist in perpetuity is precisely because it's physical. There's a thing, and people naturally wonder who owns said thing. "Intellectual property" is nothing of the sort. What it is, and all it is, is the government saying "only this guy over here has the right to copy something".
And that should last forever?
Gimme a break.
Lawrence Lessig rips him up here, and John Scalzi responds thusly:
What would happen, almost inevitably, is that copyrights of any value (positively, negatively or ideologically) would be secured by a few large private repositories, who would jealously police any new content they believed infringed on their copyright portfolio. One suspects that most of these repositories would also be publishers themselves, who would publish on terms advantageous to them (i.e., works for hire and/or assignation of copyright to the publisher after the death of the author). If you don't think it would happen, look at the actions of media companies today and the content protection groups they fund.This isn't even what "would" happen. This is what "does" happen, at least in the arena of science research; a lot of people in the scientific community decry the fact that a lot of research is locked up by a few companies that own many (most?) of the most respected journals, propelling the move towards open research that we've been seeing lately.
I think an even better argument would be to ask what would happen if, say, patents were perpetual. Would that make for better science and technology? No? Then why on earth should copyrights be any different?