I think something not measured here but potentially important is the amount of acquaintance contact people have. If you imagine living in a time before high-speed travel and big cities, the people you interacted with day-to-day were basically the same throughout your life. Maybe you weren't "friends" with these people, but just in order to live your life, you would inevitably be bumping into people that you had known…
That's your choice. I shop at the same small businesses food market every time and see the same faces year after year exchanging life anecdotes. I see the shopkeeps there more often than I see my actual friends.