900 hrs a year...six to eight hours a day, five days a week, given up to one's mandatory attendance at school, certainly can make a good education virtually impossible. It would take a very unusual individual to teach himself what was missing in an educational regimen consuming a third of every weekday; and determine what was false, and find the truth.
A dear friend of mine, having attended public school from k-12 with almost no gifted track academics despite a genius IQ, said it was like spending those 13 formative years working full-time in the sewers. Except people get paid for that, and have a choice.
If no school can ruin a good education, then no slave labor camp can ruin a good job.
I see what you're saying.
My comment rests mainly on my experience that most good parents instill a limited number of good principles in their kids which end up being learned quickly and well. When the teaching they hear contradicts these principles then the parents explain why or why not they should accept the new teaching.
But as you said, there is SO much time the kids spend in the govt schools - and the left wants them to spend even more - that the parent doesn't get as much of a chance anymore to instill those few but very good principles.
Kids need fewer hours of school studying fewer "social" programs. Govt needs to spend fewer hours passing new laws and trimming the deadwood out of the legal code, too, but it won't happen unless some profound changes are made to the people we put in office.