Not only was the late Sam Blumenfeld, a pioneer, in the modern homeschool movement but in the early to mid 1970s, Sam helped to start a number of private schools including South Boston Heights Academy in South Boston, MA, and Hyde Park Academy also in Boston. I Here is a link to the first lecture he gave at South Boston Heights where he discusses how he discovered the deliberate dumbing down of America:
https://www.podomatic.com/podcasts/shurtleffhal/episodes/2021-02-04T15_44_23-08_00