The environment selects for those traits that are better able to survive and perpetuates those traits. That is natural selection. Our society through its policies, laws, and behaviors selects for those people who are greedy. (Some call this artificial selection) We allow people to earn as much as they want and spend it how they please. Those who earn the most are better able to survive and pass on their genes, thus perpetuating their genes. So our society, by rewarding greed, artificially selects for that trait, thereby perpetuating it. Greedy people will have more children exhibiting the greedy trait until the entire population is made up of greedy people. The extent of the greed will grow too, because those who are the most greedy will pass on the most genes. People should look at which traits they want to see survive and set up policies that promote those traits/behaviors. I would suggest greed is not one of them.