From John Kay's latest blog post :
Looking at the different outcomes for North versus South Korea and East versus West Germany :
There are few controlled experiments in economics, but these are as close as we get, and the results were clear. They were also unexpected. Hard though it is to believe today, in the 1960s many serious commentators on left and right believed that Russian economic progress threatened western hegemony. Those on the left were naively credulous and those on the right victims of paranoid fantasies.
A perhaps apocryphal story tells of a Russian visitor, impressed by the laden shelves in US supermarkets. He asked: “So who is in charge of the supply of bread to New York?” The market economy’s answer – that not only is no one in charge, but it is a criminal offence for anyone to seek that position – is surprising.
As for whether "greed" can sometimes be "OK" (from an amoral perspective), read the linked article above to find out.