The benefit doesn't just exist for no reason. It only exists because of limited resources. When resources are not limited we don't display aggressive behavior.

The benefit doesn't just exist for no reason. It only exists because of limited resources. When resources are not limited we don't display aggressive behavior. We are not living in a time of limited resources therefore it is actually evolutionary detrimental for us to be aggressive. It's not a coincidence that our popular culture de-emasculates itself bit by bit every decade. It's because we live in plentiful times and our behavior (which is conditioned through natural selection) reflects this.