Public Education was designed to create obedient workers and soldiers who won't question authority.

It's not just USA schools that were dumbed down, the same think happened in the UK. I can list all the events that happened:

1. Oil workers got paid more than graduates in the 1980's. This has caused a population reversal where school-leavers could afford to live in the city, but not young couples. There was actually a teachers strike over this. Now the playgrounds have been converted into car parks for teachers who can't afford to live locally.

2. Closure of special needs schools. Originally kids with behavioral problems went to specialist schools with specially trained staff. Politicians decided to close these, and sell the buildings off to property developers. Those kids ended up going to standard primary and secondary schools - wearing out many good teachers.

3. Closure of smaller schools - they didn't have enough facilities to provide for the entire curriculum. Politicians would say the kids were "rattling about likes peas in a pod". Other schools then had to take on larger class sizes.
But really, politicians rezoned council housing for the use by retired couples. That way they could deliberately maintain a shortage of family homes in the city to keep prices up.

4. "Streamlined" education syllabuses. Mathematics and Arithmetic were merged together and dropped concepts like simple interest/compound interest. Physics, Chemistry and Biology were merged into General Sciences. Coursework replaced exam work.

5. Introduction of Foundation, General and Credit levels of exams. Basically the same course, but with different levels of exam. That way, everyone could get an A. But employers didn't recognise the Foundation or General levels, so they were dropped.

I'm not up to date but in the 1990's there was a federal "Goals 2000" program I know something about. I attended a seminar of mostly teachers and professors who knew the details. They said more than 50% of the questions in the mandatory tests were not academic in nature but designed to gauge how "compliant" students were. They went on to say that if the results were not in line with objectives then curriculums would change to influence future test results.

The one example I remember of a non-academic question designed to test compliance was something like this:
... Mary is out with her friends and one of them suggests they spray some graffiti. Everyone says OK but Mary is hesitant, she
a.
b.
c.

None of the possible answers were to say "no"...

It was explained that these kind of questions are designed to change the way you behave by omitting any option that does not "go along with the crowd".... the "goal" is to condition children to go along with the crowd and not think for themselves.