One alternative explanation is that children who are more securely attatched are more likely to be in a better social class. This is not implying that all mid-upper class children are securely attatched, but that if a child is securely attatched, he is more likely to come from a better social background. Therefore, a child who is securely attatched is also more likely to have more advantages early in life (good school, better community, etc.). This may be what is causing the child to be well off later in life, not just the fact that he was securely attatched to his parents.
I agree with you. In my own post I mentioned that I thought children need several good attachment figures early in life to have high expectations of all future relationships. I believe that a child from a better social class will have a greater exposure to those who will have the time to give it attention and therefor have positive relationships.
