All that money and he's still a mortal just like the rest of us. I wonder if mega billionaires like him have done private research on life longevity, cryosleep, mind-upload, etc. It's the only useful thing they can do with that much money that directly benefits them. Anything else (legacy, influence, children, etc.) doesn't benefit them when they're gone.
With all the billionaires we've had, the fact that no one is living unnaturally long or in some kind of cryosleep or AI simulation probably means one thing: It's simply not possible, and if it is, all the money in the world won't get you there.
There are things I don't like about him, and the way he is idolized by people that want to accumulate money. But I will say you can't really throw that "all that money and he's still mortal" thing at him because in reality he lived really below his means. So the money part is interesting, why did he try to get so much if he didn't really need it? I think (without really knowing anything about him), that he wanted money like everyone else to be independent, but at one point it turned into a game to see how much he can win.