Every single human civilization has failed over time, and my belief is that it's due to a lack of rational empathy, of understanding that if you don't have equality in your society, the conflicts you breed (whether internally or externally) will eventually cause its collapse.
It is necessary for all of us to awaken in ourselves this spirit of cooperation, for then it will not be a mere plan or agreement which causes us to work together, but an extraordinary feeling of togetherness, the sense of joy in being and doing together without any thought of reward or punishment.