I think people need to reconcile their level of interest in making new friends or finding success in innately social environments with their level of willingness to overcome fear or exhaustion. I see a lot of people in this thread basically saying approx. "you don't get it, it's exhausting", and that's fine enough if you've determined you get no value (after exploring that prospect valiantly) in doing the thing that exhausts you, but it's not fine if you do get value out of something and aren't willing to exhaust yourself.
Exhaustion for me is often a key component in anything I do. The friends that do find social interaction exhaustion and can't overcome it, I end up seeing once a year, and that seems to be ok with them, but if they were hoping for more, they need to practice being exhausted.
Lastly, if you're not practicing the exhausting things, you're practicing the comfortable things, imho. It seems more true in more cases that people aren't willing to do anything that exhausts them, so they never walk far, they never go to the gym, they get fat and isolate themselves socially... until they realize that they've suddenly become squishy, dull, and lonely, then look for a quick fix that doesn't cost them anything, and maybe post to Reddit "Any friends out there? I'm an avid reader and single player video gamer that will sometimes come out for 30 min if it doesn't conflict with my nightly 5 hour solo stationary leisure time. We could start a group chat!". There's nothing inherently wrong with that, it doesn't need to be fixed, but it services what it services and it's worh thinking deeply about whether that is or isn't worth practicing.