Here are 2 lame arguments defending copyright extension:
Olson gained ground when he invoked another clause of the Constitution, the "necessary and proper" clause, as a justification for the legislation as a matter of equity.
The court, [Olsen] said, should not say that 99 years is too long for a copyright to exist, noting that the works of Herman Melville and Franz Schubert ''weren't valued until many years after their deaths.''
No one could really think that anything is necessary about copyright law. If that argument were valid, it would justify any federal law.
The Melville argument is sillier. Melville died at age 72 in 1891. The NY Times obituary said, "forty years ago the appearance of a new book by Herman Melville was esteemed a literary event, not only throughout his own country, but so far as the English-speaking race extended. ... Years ago the books by which Melville's reputation had been made had long been out of print and out of demand. " His last novel was publish in 1857. Moby Dick was 1851. Apparently his novels were highly regarded when they came out, but the market only existed for a few years. A copyright of 10 years might have been as useful to him as a copyright of 50 years.
But under copyright extension, Melville's novel would still be copyrighted until 1961. Giving some publisher a monopoly in 1960 over Moby Dick would not have gotten Melville to write any more novels.
Based on oral argument reports and the written reports, I conclude that the liberal Justices took to Lessig more than Rehnquist and O'Connor did. Maybe we have the Bajakajian situation, whereby Thomas joined Stevens, Souter, Ginsburg and Breyer to apply the Excessive Fines against the government and force it to return $357,144 to someone who merely had failed to report it. We could still win by trading Ginsburg for Scalia. But if Thomas holds against Eldred, Lessig's lost. Too bad Lessig didn't work harder to appeal to Thomas. Well, we did.
I don't know that Friedman is really a conservative. He opposed California's Proposition 13, for example. Libertarian might be a better label for Friedman.
The conservative economists are Thomas Sowell, Walter Williams and Arthur Laffer. There should be at least one Nobel Prize among them, but that hasn't happened and isn't likely to. Liberals don't like giving awards, particularly academic ones, to conservatives.
Economic theory for copyright seems badly underdeveloped. Easterbrook wrote a superficial piece and seemed to imply that he favors clear rules, by which he may mean strong copyrights on which the market can bargain. But that only works if you ignore the monopoly inherent in strong copyrights. I think he once sided with the dental association's control of its codes.
Volokh has a detailed prediction of a 6-3 in favor of ruling the extension unconstitutional.