I tend to agree with you, but I also tend to believe that indeed, having a billion dollars (read: having no constraints) will tend to bring out the worst in anyone.

Another way to say this is, most people who earn obscene wealth who would be offended by the obscenity of it would work hard to give most of it away. Those who are not offended by the obscenity of it will be happy to keep it, so there's a selection bias to it.