The boy down the street from us has an endowed chair as a business professor at Ouachita. I see him every five years or so, and we just say "hi", because our parents are friends. The kid I called my "best friend" in grade school (though I'm not sure he called me his) is an architecture professor at Georgia Tech. We e mailed about three years ago, but we don't keep in good contact. The kid who came to our yard every day to play football and basketball dropped out of college after partying too much his freshman year. I have not seen him since I gave him a ride back home the day he left school, over twenty two years ago. The two guys in our neighborhood with whom my brother and I used to play went their own ways. I have not spoken with either in at least two decades.
I do not have a lot of "buddies" in my day to day life. I share this trait with my father, who had lots of casual "hi, how you doin'" friends, but no
real day to day buddies. I do have one male friend in town with whom we sometimes socialize. I see my best male friend living elsewhere a few times a year. I barely see my best friend from high school once a year or less these days, because I have let things lapse. I really don't spend that much time with anyone but my wife and co-workers.
I never really set out to be a loner. I love people. My wife and I get along well, and spend a lot of time together. But in general I'm not unhappy as a bit of a loner. I don't pine for what I do not have. I suspect it's either hard-wiring, or a trait so well-learned as to be embedded. I imagine myself warm, and happy, and in some ways alone.