I felt bad when I read this, because I'm one of those people that doesn't call anyone to hang out, and always waits to be invited. I had one friend that wouldn't even bother calling me, because he knew I would probably say I was busy, so instead he would just show up at my house. It kind of bothered me, but I really did enjoy the time I spent with him. It sucks, because he randomly disappeared about a month ago leaving behind notes that sounded like he intended to commit suicide. Luckily, we (his other friend, his family and I)were able to find out that he had gotten a greyhound ticket, so it seems that he is probably okay. But I really regret the fact that I never initiated meeting up, and ignored his phone calls, and since then I've been trying hard to be more social.
It's possible that you're friends aren't really your friends, but it could also be that they are solitary people, that do care about you a lot, but just don't know how to properly express it.
We've talked some too, so I know your an interesting and intelligent person, so there are bound to be people in the future that will be happy to hang out with you, if your current circle doesn't get there shit together.