Which is kinda what he's saying. He explicitly says that if he could do it over again, he'd have stopped at the point where he could live comfortably but not extravagantly.

I used to wonder how people like Bill Gates could resist walking away once they'd made their first ten billion, and doing something fun or personally fulfilling. If I were Gates, I'd be living on the Moon and looking through a telescope at Mars. But upon thinking the question through a little farther, I realized that if Gates were the type to do something like that, he'd never have made that first ten billion in the first place. He would've quit after his first ten million, without the resources to do anything but live well on Earth with the usual expensive toys.

A depressing paradox, when you think about it.