This is the calculus of movie making. Makes sense to me:
Hollywood has always made most movies for a juvenile crowd. A producer, I think his name was Zanuck, worked out the logic like this: Girls will see anything boys will see, but boys will not see most things girls will see. Younger kids will see anything that older kids will see, but older kids will not see things made for younger kids. Adults will see most things that older teenagers will see, but older teenagers will not necessarily see things that adults would see. Therefore, the correct money-making demographic to make a movie for is a 17 year old boy.