The traditional rationale for the existence of the State is grounded in the nastiness of nature and the desire for security: humans try to survive the vagaries and threats of nature by forming families.
But families are themselves small, vulnerable units – a small, isolated family is easy prey for both human and animal predators. If it were just one man, his wife, and two or three kids, who will hunt, who will farm, who will defend the family, who will cook the food, who will make the weapons needed to hunt and defend the family?