"But I think an artist does deserve to control his work. And that includes being willing to sell that control to a corporation. And that includes determining how the work is used, reproduced, or promoted by others."
Does control of your work override control of my property where it resides? To what extent is control feesable? Should I be charge for performing a song every time that I find myself humming it in public? How much control can I reasonably have over other people's free actions? Much of "fair use" resides in the fact that regulating these answers would prove burdensome and counter-productive. Congress knowingly put in the rules for fair use because they determined that a creator does not have an absolute right to absolute control.
"As for lifetime + 95 copyright. Well, even that is not simple. It's not just about earning money for the artist, and possibly the first generation of their descendents. One problem is big cultural icons, like Mickey Mouse. What would happen to them, and the companies they are a part of, if these icons became public domain?"
When folks created their works, they KNEW, because it was the law at the time, that their works would enter the public domain in 35 years. The public domain loans the creator a limited monopoly on their work, and in exchange, the public domain takes ownership of that work after the time has expired. This is the way that copyright works. It's in the US Constitution. When the public domain does *not* get the copyrighted work, this contract has been broken. This is the current case, when copyright works get extensions on their copyright.
As to what happens to the companies, who cares? Really. They know the rules of the game. They know that they have a limited copyright. It is up to them to have a business model that is geared to creating new works. If they fail to do this, then their leadership has failed the investors.
"And what should copyright allow? I didn't see any answer to that here. Simply saying the lifetime of the artist doesn't seem satisfying -- a book published just before the authors death has a certain value to the estate, based on royalties. Some of those royalties are a legit part of the estate, the question is, "how much?""
That's a good question for debate. I don't know all those answers. "Death" is clearly too short, but "Death of your grandchildren" is clearly too long. What is a fair time to allow for profit, and fair to the public domain, which allows the creator to have the copyright?
"Why is intellectual property different than material property? Suppose that after the first owner died, a house was only private property for 50 years. It could be sold, rented out, whatever, but after fifty years, it was public space. Sounds silly, right? Why should intellectual property be different?"
It is different because the US Constitution makes it different. Copyright and intellectual property, such as patents, are mentioned in the document, and are regulated differently because of it.
Secondly, intellectual property is not a house. It's not even property. It's a temporary right granted by the Constitution. The key words here are "temporary rights." As for property, there can be only one instance of that property. It is static and stays in place. "Intellectual property", by which I mean "copy rights" and "patent rights", is infinitely recreatable. It is this recreatability that is regulated by intellectual property law.
You may not know it, but intellectual property also has many mechanisms that FORCE the creator to licence the property, whether they like to or not. Once a song is publicly performed, anyone can record that song without permission, as long as they pay the mechanical copyright. Works may be quoted or parodied without permission. Buyers of books have the right to resell the book, even though the copyright holder owns the copyright. Copyright holders have the "right of first sale", but their rights end at that point.