I think that may very well be true and you have outgrown your friends. This happens sometimes when you take the time to work on your self and grow but the people around you stay the same.
I agree with you. Looking back, I think I subconsciously dropped some friends along the way because we seemed to be moving in different directions. It is better to have a few real friends than have a lot of people around you, that you aren't sure about. I love solitude and I think I have too much of it sometimes.