I've never had more than one or two friends at a time. I find maintaining relationships too much work and it just not worth it. Right now, I have exactly two friends and their children or spouse in my life. I try not to impose myself on them too frequently and appreciate that they do the same for me.
John Bradshaw said that he only had brain space for 5-7 good friends. And he had to be careful about new persons taking time from his attention to those friendships.
And, it seems that we all get less interested in more persons, and more interested in ourselves, as we age. Even if i could be as i was when 25, i would not.
I have never had a wide circle of friends. Introverts tend to value quality over quantity throughout life. That said ... At present, on an in-person basis, I have 4 casual friends and no close ones. My youngest sibling is 72 years old and in poor health, the other is in better shape but 5 years older. Parents long-dead. Even one of my children is gone. And my wife is in a similar situation.
So ... we do our best to get out of our comfort zone and Do Things With Other People, but it's slow going for us. We're not picky (one of my acquaintances announced last week that he and his wife are going to Ken Ham's Ark Encounter for their vacation this year ... so no, not picky AT ALL). Still ... sometimes I think I'm going to end up being that guy who dies while watching TV and no one figures it out for a couple of years!
The older we get, the more entrenched we become and less likely to hang with anyone different. Especially males. And especially in the age of DT where we find out that many people we know are so different than us.
I get that totally. I'm down to 1 or 2 now, and I'm not certain about them. It is a natural fact, I suppose, sometimes due more to circumstances than intentions, I think. And if one is not a "joiner," the process seems to accelerate with the passage of time.