I tend to believe that the Madison Avenue advert executives were only responding to the development of a new market that emerged as a result the move to merge many small schools into a few large suburban schools localities chased the economic efficiency of mass produced education.
The byproduct was the creation of a new social group of that had never existed before. Instead of a handful of neighborhood kids roaming the hood there were suddenly hundreds to thousands roaming a single school and creating their own subculture in the process.
In the end the youth began socializing themselves into their own culture rather than adults socializing the youth into adulthood.
At this point we are a nation of children.