Any system that unshackles restraints on how much a person can acquire in this life promotes greed.  As it would turn out, capitalism so far has been best at it.
 
This is the core issue where morality, economics, and politics meet.  How does a country balance out that "greed" vs need for the betterment of as many of its people as it can?  Communism and fascism tried and were found to be very lacking.