I feel exactly the same way, but I think what you said about the dissolution of family could be applied to communities too, a collection of people where every one is important to the whole someway or another. I've never felt like I belonged anywhere but in my clique of close friends ever since I was in high school, and most people now cling to groups so large that they really have no meaning in them or online "communities" where they are only bound together by some common interest.
Although I guess I might just be a schizoid who, after lurking on image boards like this for 7 years, hasn't posted a single thing. I have always considered myself to be an autodidact instead of socially awkward though. Mostly due to the fact that I do have my 'tribe' in real life. My close friends are a good way for me to share and flesh out my ideas, but they don't engage with me out of compassion, but interest in said topics and trust that we won't just call each other gay and end discussion there.
My 'tribe' I found to be the only outlet left to "forge yourself" guess having like minded friends in real life keeps me from posting on sites like these, where people like us, who are influenced by not exposing ourselves, are forced to learn on their own.
That being said these friends can only get me so far so I often do find myself having to develop my ideas by myself.
Despite everything you said about the thing you think is missing, I say that a real outlet to help define yourself does exist, granted that you may never be able to find it. Gather yourself some like minded people in the real world THEN you can chat with them online. That's the only way I've been able to start and maintain an online relationship of any sort. Put yourself into a program or go to some place regularly where you're forced to be around people and I'm sure you'll be able to find the people you're looking for.
Best of luck,