As the optimal strategy for iterated games, Tit for Tat long ago became the norm and basis of human social coordination. It is manifest in our sense of fair play, in our customs and laws, and in all our economic exchanges. Tit for Tat is then a strange attractor for human societies. They all tend toward it, homeostatically. The further you push a society away from Tit for Tat, the harder will it try to get back.
Prevent a people from responding to tats for a long, long time, and eventually they will snap. The frenzy of the explosive rush to restore equilibrium will manifest in a million tits for every tat. Those who had lately done well by tatting will find themselves all tits up.
It will be a bloody ugly rebound.