Well the difference is this: If I'm sitting at home every evening because I'm too exhausted from work or come home late every evening and thus have very little

Well the difference is this: If I'm sitting at home every evening because I'm too exhausted from work or come home late every evening and thus have very little social interaction is a very different limiting factor than what caps the number of people in a military unit that I can keep social bounds with. In fact I might be very effective at keeping good working relationships with a large number of coworkers. That doesn't translate at all though to having many friends. At one point in my career I knew everyone in an office of about 100 people by name and had frequently very pleasant conversations with then. Yet I had fewer casual (as opposed to close) friends in the city I lived in than can be counted on one hand.