Is his life that much better than if he had taken the money and run? I am a big believer that the best life is found at the upper, upper middle class level where you have enough money to do almost everything you want, but where you can walk down the street without bodyguards.
If someone offers you personally $1B, you take it, and go live the rest of your life comfortably without any worry of ever having to work a day ever again. Do you really think having $3B vs having "only" $1B matters in the grand scheme? I surely would prefer a billion over a potential xBillion. There is more to life than working your ass off. Zuckerberg wanted power, not more money.
That's basically what Notch did with Minecraft, and frankly he seems to have been bored since. You should never underestimate how important wanting to do something interesting and worthwhile can be.