Re: "Once these obscenely rich people have grown out of their thirst for continuous success"
Warren Buffet is trying pretty hard, in conjunction with Bill and Melinda Gates. And I think Melinda should get more credit than she does. She married the money and then tamed some of Bill's more anti-social/business behaviors. Then started giving the money away.
There are quite a few more, but they don't get the press that Musk, Bezos, et al get. They quietly amassed fortunes and are quietly giving them back without fanfare because they are intrinsically good people who happen to be good at money management and/or lucky.