I grew up and finished high school before DoE came to exist (1979). I guess I was in the lucky group.
Around the late 1980s....I worked around older NCOs who had kids in school, and 'changes' were being discussed. 'Sarge' was disgruntled over various little changes....where the kid didn't 'get' it. A change in education tactics was taking place, and the teachers were wasting twelve hours....trying to get a simple process across (the old process would have consumed four class-hours).
In the 90s....these changes started to occur in college environments....where they were getting less-than-average students, and expected to bring them up a notch. I'd offer the observation....this simply meant colleges were starting to set themselves up as the 11th/12th grade-plus education system (what was not taught in high school...the college would make up the 'loss').
Around 2011, I worked with a guy whose daughter was wrapping up high school....considered highly gifted....and applying for George Mason University. They accepted her, but required a English and math assessment test. Failing both....the college required her to take a pre-college course (actually two courses). Dad had to pay for this and was peeved....why didn't she have the knowledge required for a 12th-grade assessment test.....was the question asked. I didn't say much but thought....well....she's really not so gifted.
This 'gifted-label' gets tossed around a good bit these days. I imagine that the majority of gifted folks....are actually less than average. But it's probably a bad thing to mention this in public.
So while all of this was going on....more fake gifted-teachers completed college, and got jobs in schools across the country.
I doubt that this was a design or planned-out....but you end up now with most kids probably at the 8th/9th grade level....finishing high school, and colleges wasting 1 to 2 years....teaching 11th/12th grade topics, and most folks wrapping up college at a junior college level. The cherry on this cake? You borrow $80,000 in student loans.....have what is a junior college degree.