For the mega wealthy I would guess it's not really about the lifestyle but rather the power and influence. At a certain point the money is just numbers because in reality 20 billion is too much for anyone. So then it comes down to power, influence and Ego. I think a lot of billionaires lose touch with the real world and also lose a lot of empathy in the process. Murdoch can go to a casino and drop 5 million on one hand of poker or roulette wheel (yes it happens)...thats just disgusting considering what good that money could do.

For many that kind of money or the path of getting to the point of having that kind of money turns you into an Ass@#le.