Go read one of the most important books in the past twenty years, Robert Wright’s Nonzero. Our entire Enlightenment Experiment has been about positive sum games. Open-competitive Economic Markets, Science, Democracy… these are all examples of systems set up to harness competition and produce positive sum results for all.
Alas, there are forces in human nature that always trend toward ruination of such systems. Winners tend not to want to compete as hard, next time, so they use their wealth and power to cheat! It is called oligarchy; the very thing that wrecked markets and democracy and science in all past cultures. Every single last one of them.