Although I have had friendships in the past, I do not maintain those friendships once I move from the geographic area. For the past year and a half, I have not had any friendships to speak of. At present, I don't have any friends and do not try to have friends. Moreover, I have little to no desire to have friends, probably because it is easier to avoid socializing than risk the general anxiety that comes from the rejection and humiliation.
With a "winning" personality, even the worst people can be successful. In the United States, a mass murder named Ted Bundy had such a tremendous personality that he cultivated many friends from all walks of life (before he was caught). With a "losing" personality, even the most intelligent, friendly, honest people will not be successful in life. Success is meaningless if you have no one to share it with.
I stay away from social situations and push people away when I am in social situations. Just recently, I reflected on my life and realized that I had nothing in my life to keep me from participating in life. I know that I am smart, attractive, honest, and have a high paying job -- everything people strive for -- and yet I have low self esteem, no friends and no social life. I've worked on all aspects of my life driven by the need to understand what is wrong with me. Maybe I was too dumb. I now have several college degrees. Maybe I wasn't athletic. I drove myself to be strong in swimming, running, and weightlifting. Maybe I was mean spirited. I bent over backwards to help everybody out. I am now at the point where all obstacles have been removed to reveal my social under development.
Have you tried y'know, talking to a therapist? It's their job to figure out what's wrong with you and help you find a way to fix it.
It's interesting how you frame a paradox between your social development and your accomplishments as a person. And it sounds like you are active and living "the dream", looks, money, and intelligence. Of course society may fabricate that that is what everyone wants/needs in life when really we could all live within our means. I think that a lack of social development comes from a lack of self; not understanding who you are deep down inside. For most people who are introverted and avoid people, they interpret what some might say as "being alone" as "resting in solitude". We must be conscious at our real thoughts despite what others may think or say and follow those thoughts to fruition. Instead of seeing your solitude as something more or less a preference, you see it as something negative.
Now when you say social underdevelopment, just how bad do you think you are? Do you feel pressured in social situations? Did you have any bad experiences socially?