If you look at the Patent Laws, the first thing you read is that they are set up precisely so that inventors have time to profit from their inventions (if they pursue them diligently), but the rights lapse after a reasonable length of time so that inventors don't become horrible Holdfast dog-inna-mangers putting a drag on the economy.
On the other hand, Copyright laws are a drag. I mentioned yesterday that copyright holders don't deserve some of the payments that are given to them. This paper explains why. It's from the Yale Law Journal. It is about the law creep, or grade inflation issue from which US copyright law suffers. The paper does covers music publishing, but is focused on other issues.
In brief, there are few things that require licenses from the copyright owner under law. But it's much better for someone wanting to use a piece of copyrighted material to seek a license from the owner and pay it. This has consequences down the road as the mere existence of licenses for a use in the real world is then cited by lawyers to 'prove' that this use requires a license. So, the types of things requiring licences get broader and broader.
They call it "doctrinal feedback".
Warning: it's a 70 page PDF. There's a response to the paper on the site as well.
 Joseph Campell, The Hero with a Thousand Faces:
For the mythological hero is the champion not of things become but of things becoming; the dragon to be slain by him is precisely the monster of the status quo: Holdfast, the keeper of the past. From obscurity the hero emerges, but the enemy is great and conspicuous in the seat of power; he is enemy, dragon, tyrant, because he turns to his own advantage the authority of his position. He is Holdfast not because he keeps the past, but because he keeps.