I have a couple of issues with that point. The first is that the author still has the potential to make money from that work, though I will agree that very few authors are in a position to do so. The second is that most out of copyright works sit in storage (or are destroyed) without generating revenue for anyone. Many of those works are only coming back to light today because of massive digitization efforts, and even then most of those works are going to remain so obscure that they will never make money for anyone.

For the most part, I don't care if those obscure works wither away. It is the important works that matter. Should works like "On the Origin of the Species" forever be in the hands of Darwin's estate? Should the words of Martin Luther King Jr. forever be in the hands of King's estate? Keep in mind, copyright pertains as much to Darwin's and King's words as much as it does to a Mickey Mouse or Harry Potter. While it would be sad to lose the mouse or the wizard, it would be a travesty to lose the words of the biologist and civil rights leader.