It has nothing todo with what is 'natural'. There is no natural right to land ownership - it's just the system we choose democratically because we believe that the advantages it brings outweigh the certain misery it causes the impoverished. Few of us believe that abolishing the right to Private Property would, on the whole, bring about a net gain for the majority. Personally, i don't believe that the Maisel case has much to say about abolishing Copyright. That doesn't mean i'm not in favour of doing so, but Maisel is an edge case.
Actually, the most prominent scholars in this field often do include land ownership as a natural right. John Locke, the modern father of natural law, described natural rights as, "life, liberty, and estate". I think its largely settled philosophy now.
Copyrights are still much more debatable. The main defense for pro-copyright activists are that they're necessary for the economy. I tend more and more to the belief that the economy will change as a result -- a freer economy, but a different one.
