Well for me I do think all people want to have the most money we can have. Even a wealthy man will say he still wants to make more money then he does already have.
I think it is just how us humans are. There is people in the world that has Billions of dollars and they still do work very hard to make more money.
I do not understand why they do this but we can just look at worlds richest people. They all do still work to make more money. Even the rich people that has enough money they can not spend all of it still do work.