Even if any singular ultra wealthy person is doing nice things, you'll still have bad actors like the Koch brothers who are actively trying (and succeeding) to subvert our government systems to their own benefit.

https://en.wikipedia.org/wiki/Political_activities_of_the_Ko...

Which is why we need governmental solutions, laws, taxes, etc and can't rely on just good will.

I havent read the book you recomended, but I will check it out. I'd also recomend the book "On Corruption in America: And What Is at Stake" as it's a great description of how global elites have largely captured government for their own ends since the gilded age.