I think he's misinterpreting a lot these people who are "too driven". Perhaps the reason they don't stop after the windfall is because they're working for themselves and doing what they love? Freedom is the ability to choose what you do, it doesn't mean not working.
I'm not even sure it's accurate to say that "most" don't stop. I personally know some very driven people who have "retired". They're doing things now they feel are more fulfilling or more interesting.