I'm old(er) mid-40's, single, no kids, and never married. I don't have much family or close friends. Hookup culture is de rigueur but it doesn't interest me. Where I'm at, there isn't a context to meet people and most random people in public around keep to themselves and treat me like I'm invisible. I do volunteering but that also doesn't go anywhere.
If you have to constantly take the social initiative, then you're carrying the relationship. Sometimes absence is better. Instead of dwelling on loneliness or self-pity, keeping productively busy seems a better alternative.
I'd like to have a family and kids, but an inability to find and make friends precludes that. The thought of getting old alone, having no one to check-in on me, no one to bury me, no one to care that I'm gone, and no one at a funeral seems depressing. I don't see how I won't end up in a "potter's field" somewhere.