I think its just laziness and lack of patience as you get older
if you think about it, learning the odd new tech is absolutely nothing compared to going through primary and high school. Its just so long ago you don't remember the incredible hours spent learning stuff you were never interested in.
Not sure how accurate, but apparently when they studied Einsteins brain cells some time after his death, they found the cells were in a great condition equivalent to that of a youth. At the time of his death he was still trying to work out 'the theory of everything'.
