Worse, he didn't just piss away his own wealth. By running D'Anconia Copper into the ground, he violated his fiduciary responsibility to the company's investors.
That is beside the point. He is protecting the wealth from the looters.
He uses his family's fame to bring in looting investors to his mine in Mexico, then it is revealed that there isn't anything of value there. The investors were looters, so D'Anconia succeeds with his goal.
Are you saying that it's OK to violate a contract if the other party to the contract is a "looter"? Why not just avoid making contracts with "looters" in the first place? (D'Anconia, after all, could have simply cashed out all of his holdings and let his successors decide how to deal with the threat of nationalization.)
Hmm, in general I agree that the proper action would be to simply not do buisness with those who cannot add value (the looters), but within the logic of the book it is clear that this is not an option. As someone has pointed out, it is a given that the looters are waiting till the mine is producing to nationalize it and the railroad to it.
D'Anconia has agreed with Galt to stop carrying the looters and so he plays the spoiled playboy. Sure, he has a certain duty, but that goes both ways, and if the investors are not adding value then what duty does he have to them other than to do as he pleases? They are trusting that they can make money off of him based on his family history, nothing else. That is, there agreement amounts to: "Go make money as you always have. We would like a share, but you do the work."
I agree with the comments of unalone and guiles. They point out what I don't like about the book, but I didn't see anything wrong with this subplot within the logic of the book.
The investors added value by providing D'Anconia with capital. Once D'Anconia accepts their money, his duty is to manage it in good faith. Whatever character flaws the investors have (e.g., excessive faith in D'Anconia's management skills) do not excuse him from his fiduciary duty. If he doesn't like owing a share of his profits to people who don't contribute any effort to the company, he is free to liquidate his own shares so he can start a privately-held enterprise.
The company was going to be nationalized, essentially stolen from him, anyway. Thus, investors didn't matter in his decision to give the nation nothing in return for stealing his company.
If I tear your wallet out of your pocket and set it on fire, I can't escape prosecution for theft by saying "there was this guy coming down the street who was going to mug us anyway, so you haven't really lost anything".
