The difference is that with communism a natural human desire is punished, while in capitalism it gets rewarded. I mean a desire to do a good for himself, and only himself, ignoring the needs of the others. Maybe we don't like it as the society, but that's the people's nature.

It seems that it's more effective to leverage this natural desire (as in capitalism) rather that punish it (as in communism). The important part is "natural", i.e., people are born with it, as well as animals, and you cannot prevent it. That's not a minority at all. So the only way for communism is to constantly fight it on a great scale, which is possibly with turning into a authoritarian government.