In addition to poor nutrition, the prolongation of childhood, there is the clear de-education. This is not miseducation, this is a policy to NOT allow one to be educated.
By removing streaming, by lumping children together regardless of I.Q. and ability (or the lack thereof) education is slowed to a crawl. The bright child becomes bored and sees no benefit in schooling. The dunce child would not be challenged and wallow in their ignorance.
All gains made between 1950 – 1970 were eroded so in slow and measured steps the educational levels that existed in the 1930s would be reintroduced.
These steps were done quietly and slowly. Hence the parent who left primary school in 1958 would see no great discordance between what they learned and what was taught in the early 70s. This slow degeneration of education prevented notice, dissent.
This was the purpose of the slow descent; to avoid awareness.