Although many studies have shown the correlation between secure attachment during infancy and increased well-being later in life, there are many other variables that have the potential to affect this correlation. For example, a responsible and nurturing caregiver (who took time to encourage a secure attachment) would also be more likely to actively find activities and playmates that would make their young child happy. They are also more likely to encourage their child to make positive choices that would lead to a better life later on. In addition, the activities and friends a child chooses during their younger and teen years can have a large affect on their personality and development. If they are snubbed by their preschool playmates, their early security may vanish. If they are accepted by a "bad crowd," their academic performance may suffer-- which in turn will most likely lead to a decreased quality of life later on. There are many outside variables which could affect the causation of this relationship between secure attachment and later contentment.
I would have to agree with your assessment. You can't just go from saying that a child who has secure attachment with his mother during infancy will have better well-being later in life. There are so many other factors that weigh into how one's life will turn out. I thought you mentioned some good examples of this.
