The original concept of free public schools was to provide educated employees for businesses/employers.
It also was a slap at European standards where only the elite & wealthy could afford to PAY for schooling THEIR kids.
Good post, but I’m not sure about your last point. Public education is built on the Prussian model imposed by Bismarck in the 19th century. He saw public schools as the ideal strategy for propagandizing children in the various Prussian states and raising them as unified Germans.
Says who? That's not what the original founders of it said.
We, then, who are engaged in the sacred cause of education, are entitled to look upon all parents as having given hostages to our cause; and, just as soon as we can make them see the true relation in which they and their children stand to this cause, they will become advocates for its advancement, more ardent and devoted than ourselves.- Horace Mann, "patron saint of progressive education"
https://books.google.com/books?id=EgcNAQAAIAAJ&pg=PA210
It was always about consolidation of power. That's their own words. Who uses this kind of language - "hostages"?