I think this is especially sad because the creator isn't even benefiting from the copyright - talk about incentivizing, right? It seems almost the opposite of that in this case in particular I would be less willing to create knowing someone else was making 2 million dollars a year off my work, a hundred year later.
Perhaps there should be a clause of 'professionalism' added to the copyrights. I.e. a person who is doing a professional concert or is benefiting monetarily from singing 'happy birthday' should be considered infringing on a copyright but those who are performing it casually are not. Does this solve the dilemma of protecting the work but still allowing it freedom in the culture?