I probably came off as more "anticapitalist" or "collectivist" than I really am, but the point is important: betraying your partners has long-term consequences which aren't apparent when you only look at the narrow version of this game.

This is actually the real meaning of "selfishness." It is in my own best interest to do things for the community.

The mantras of collectivists and anti-capitalists seem to either not realize or ignore the fact that greedy people aren't really doing things in their own best interest if they are making enemies in the process.