No society can exist without social control. ~ Peter Berger
A sense of cooperation is insufficient to have an orderly society. Societal organization is based on social control.
The eusocialism of insect colonies has traditionally been explained by kin selection. Sisters supposedly have a vested interest in the well-being of the hive. But colony members are often not such close relations.
To maintain genetic diversity, honeybee queens routinely mate with 10 or more drones, resulting in multiple patrilines among hive workers. Ant colonies may have multiple queens, and thereby workers may be distantly related. Yet such colonies effectively function as a super-organism.
Colonial fission in eusocial insects is prevented by policing. Workers who try to lay unfertilized eggs are attacked by others, and the eggs destroyed or eaten. Genetic diversity works against any individual or group gaining undue advantage. Eusociality involves enforcement, not just unstinting cooperation.
Social control mechanisms can promote group-serving behaviors and suppress self-serving behaviors in human groups in much the same way as in social insect colonies, despite the large differences in genetic relatedness. ~ David Sloan Wilson
People have faced competition at the societal level for millennia. Societies thrive or decline regardless. Even lacking external pressure, cultures may diminish and even die out.
Beyond the fact that cooperation is psychologically as well as socially rewarding, individuals suffer if their culture erodes. Hence efforts that are group-serving are also indirectly the individuals involved. The fact that there will always be cheaters means that there is always a benefit to social-control mechanisms.
The eternal nemesis of social regulation is corruption, which is simply the continuation of the urge to cheat that necessitates social control in the first place. Corruption is the reason that societies collapse from within.