Thing is that bad management, corruption, and so on, have happened in every human society that has ever existed. A political system isn't magically going to change that. What a political system can do however is create different selection pressures for behavior. Capitalist system selects for different kinds of behaviors than a communist one. As we see with the case of transition from communism to capitalism in eastern Europe, the selection pressures of capitalism result in far worse things happening than under communism.