Considering that beginning in the late seventies; that is about forty years ago, the intervening two generations have been subject to various protocols designed to limit their intellectual development. Unless new protocols are implemented, the decline will, as the graph above demonstrates, continue.
It seems plausible that those at the top of society are aware and have and are creating a special ‘caste’ where activities implemented in the 1950s are utilised.
One assumes toilet training is understood at the high levels not simply to deal with laundry or rubbish but to imbue the infant with that sense of control. It cannot be over emphasised that the infant who can exercise control of his/her body gains a sense of self as a base. What is gained in those first months of life can not be later imbued with the same effect.
One assumes nutrition is understood by those of the higher caste and children are better fed as infants.
One assumes that life experience is appreciated, and those of the higher caste are allowed to play and think and experience the world so as to gain an understanding that goes beyond computers and smart phones and what is told to them by others.
One assumes that schools for the higher caste are streamed so that a child with an I.Q. Above 130 is not placed in a class with a child who has an I.Q. Below 120.
One assumes that children will be pushed as far as they can go, and that learning is greater than reading a wikipedia page, or playing a mindless game.
One also ponders how large a working class is required when robots will be performing many of the manual jobs.
And it is with some suspicion one views other nations, which may not have implemented the dumbing down policies.