I think I would boil it down and say a form of money exists that the Federation/Earth uses and that while not a utopian society,I would say that a unified ideal exists in that,and I think it is pretty self-evident in most of Trek and really what I think Roddenberry wanted to portray,all the people of Earth are a unified people and that while you might come from North or South America,Africa or Asia....whereever doesn't matter. People of Earth regard themselves as Terrans and not by any specific nationality in the future. Greed only really exists in the more rare aspects of humanity and that knowledge and exploration are the more defining aspects of the people of Earth.
