Whenever I see people say: "I don't get it, if I were <insert billionaire's name here>, I'd immediately ".

Anybody who is the kind of person who would spend their money to fix societal problems isn't going to wait until they're a billionaire to do it. They'll do it as soon as they think they have enough money to make a difference. That's what will prevent them from ever becoming a billionaire. It's a survivorship bias thing. Every billionaire you see is a person who could have fallen into the "trap" of helping other people with their absurd, vast wealth. But, they survived that temptation and instead kept accumulating wealth like a dragon in some fantasy story.