I think I'm with the other commenter on this one. It's a fundamental truth that only a rare, and very off-kilter, personality will earn their first $100m dollars and think "Gosh, I need more money!" Then continue working long hours to become billionaires despite already having enough to retire to a private island with a full time maid and butler or spend their life on philanthropy.

To these people it starts to feel obvious that Ayn Rand was right, because Ayn Rand would have agreed with them. They come to feel that they were rewarded because they are more righteous than others, and they are more righteous than others because they were rewarded. Capitalism becomes a religion, rather than a means to an end and money becomes it's own goal instead of a symbolic token that represents real wealth. The piece of paper is now worth more than the things it can buy.

Eventually, due to the broken feedback loop that social order was meant to provide but no longer does, they lose the common moral boundaries that tie them to other men completely and become a special kind of sociopath.