There were changes going on back in the early 70s in high school. A lot of my classes stopped being about teaching the subject and became places where our teachers would "rap" with us about things (so coool, man!). They would waste all kinds of time (we didn't care, we were teenagers) and then just give us good grades anyway.

And then a lot of those teenagers went on to be teachers, probably with the idea that they could skate with the minimum amount of work AND brainwash a bunch of youngsters with whatever numb-headed ideas they had, basically becoming the Cool Teacher themselves.