How can it be unfulfilling to be able to literally do anything you want, anytime you want?
Think of all the good you can do with 2.5 billion dollars. That alone would be very satisfying.
As if money gives you 'the ability to do anything you want, anytime you want'
How is it hard to understand why someone who created one of the most popular games in history is struggling now that he no longer owns it? You can't buy that kind of experience, just the same way Shakespeare couldn't buy himself a new play.
The dude made his masterpiece, and probably fears he won't be able to achieve something similar again. I imagine he looks at the rest of his life and thinks, 'what am i going to do, sit around buying cars all day?'
Imagine a penniless entrepreneur who risks everything on a business idea and succeeds. After building his empire from the ground up, he becomes a billionaire by selling his company. For twenty years he worked hard and saw his power grow and grow... more money, more success every time he turned around, and all gained by his own hand.
THAT is the experience of his lifetime, not the ultimate payout. Now he has billions, but no more say in his company. No one needs him to guide them. He doesn't have the power to make decisions and shape the future. He is politely told, "thanks, now enjoy your bugattis."
For people who have the power to create, driving around in a fast car isn't their fantasy... when their work is taken away, what do they have left? How can buying nice things compare to the thrill of creation?