As a grown up I need money to survive. It's not about any illusions about taking over the world or getting rich, I'm happy as long as I can afford a home, food, and in the future perhaps even enough money to buy a house or support children. Either I get a full time work and spend 8 hours per day getting the money I need for that - which means I'll have no time to work on game development - or I try to make money out of the game development so I don't have to spend all those 8 hours on something else.
I can't see a "the more money you get, the more money you want" aspect in this. I mean, how is this exclusive to people who are into creative stuff, you could say that about anyone having a normal work too, right? We all need money, but because I'm a game developer who want to sell stuff there's suddenly a major risk that I'll turn greedy and evil?