I can understand that. I used to be much the same way, and honestly, I wish I could tell you what changed about that allowed me to move friendships beyond just the "casual acquaintance" stage, but, frankly... I have no fucking clue. Hell, maybe nothing changed and I just got lucky, I wouldn't know since I'm not even meeting any new people anywhere as of now.
I guess a few things I can say is firstly, familiarity and just spending time with someone can lead to friendships. I became reasonably good friends with the dozen or so people around my building last year I saw regularly. Some, almost immediately, some, not until halfway through the second semester. I also remember that it was usually one good conversation that cemented the change from distant acquaintance to someone you actually enjoy talking to. Secondly... I hope this doesn't sound rude in any way, but just being real, perhaps learning to make friends with people you don't necessarily immediately wanna be besties with is a skill you should develop? I mean, knowing how to click with people and get them to like you is an invaluable skill, and, let's face it, when you're trying to impress an employer at a job interview, networking, trying to start your own business or whatever else along those lines, well, your knowledge of pop culture and comic books ain't usually gonna do you much good.
And as a final little point, truth is, not every friend is gonna be the type of person who you'll tell your deepest, darkest secrets to, and who'll completely change your life. Some friends are just people you occasionally share a coffee or a smoke with, some who you just joke around with, etc. As an introvert, I used to really only want one or two close friends, but honestly, I've learned that every friend, even every acquaintance you meet is valuable. So, maybe you won't find your "friend-soulmate" right around the corner, but, hey, sometimes just talking to people is nice. I've gone weeks or even months without that at times, and maybe you have as well. Sometimes friends come in unlikely forms and places.