Judging by your comments, it sounds like you work in a pretty good school system. Many school systems are good. In my area, they are generally terrible. Granted, it's been 20 years since I was in high school, but my school experience was very different. I had to re-teach myself math because of the New-math craze, and my grandmother taught me how to read phonetically because my school was on a Whole-Language program. I had a grade school teacher tell the class that she didn't like math. When I brought a Tolkien novel to grade school another teacher told me that she couldn't understand Tolkien. In 5th grade my teacher discouraged me from testing up to higher level reading material because it was not work-book based and it would have been more work for her to grade. In middle school, when I was placed in the "gifted" program, I was taken out of English grammar class to make time for the gifted program. When my mother complained about that, the gifted program's teacher told her that I was so smart that I'd get a job with a secretary and wouldn't need to know how to spell. In high school I had gym teacher who would watch his student aids physically abuse underclassmen. My psych teacher would subtly ridicule the dimmer students in her class. Another teacher would openly allow teen girls to sit on his lap. One administrator forced programming classes to turn off their computers because of a computer virus outbreak, but the school had no Internet connection and no evidence of the virus in the school. I had a few good teachers who obviously wanted the best for us. Some were just jerks, but tolerable. Most seemed indifferent. A few of them I'd like to run into just so that I can give them a piece of my mind.
My baby-boomer parents, on the other hand, wax poetic about the wonderful times they had in school. I can't say how many movies I've seen or books I've read that refer to high-school as "the best times of our lives". From my experience, that status had ended by the early 90's. So when flyneye wrote "public schools were ruined long before people began fleeing to private schools.", yeah, I have to agree with that.
On yet another hand, I worked for the past 15 years for a private school. While there were some pretty ugly warts from time to time, with very few exceptions, the teaching staff was amazingly competent and dedicated, and they did it for about 25% less pay than their public school counterparts.
I'm not blaming any one factor for the low quality of so many of our public schools. It's been culmination of decades of well-intentioned but wrong-headed polices combined with incestuous protectionism from the teachers unions and lackluster leadership from administrators promoted to the point of incompetence. Going to a school board meeting won't help much in regions like mine where the single thing that school systems can't sacrifice is the football program. If any parent happens to live in a school system that is good, then by all means they should use it and get involved to try to iron out the wrinkles. But if not, I can't blame any parent for taking any means necessary to get their kids out.