Once you start to have money, you get a money dependency. No matter how rich you get, the “baseline you really need to live the life you want and nothing more” growths together with your wealth.

Take lottery winners and ask them if they could give away half of their gains. Will you be surprised if most of them say no, even though the day before they would have set their “minimum needed to live a happy life for the rest of my days” at a much smaller fraction of it?

Now take a similar population, but who in addition rationalized them deserving that money through their hard work and talent.