Just about everybody who has been in college can remember professors who while knowing their subject were absolutely horrible teachers. College is supposed to be where the student teaches themselves and uses the expert for guidance. This is why college requires ZERO education experience and provides ZERO education training for professors. Children and teenagers in public schools are a TOTALLY different situation from that of even a public college.
Anybody with experience in education should be able to inform you if you ask what the biggest issues are for education of the immature... FYI, knowledge of the subject is not on the list! I bet you that many USA readers here will remember a time in school when they had a guest speaker who wasn't treated respectfully or a substitute teacher who was unable to get the lesson completed (it is to the point that I rarely had a teacher tell the substitute teacher continue their plans unabridged. Yes, I realize from experience one can't always just hand it off so easily.)
A motivated child acting mature enough for a little bit of time will learn ON THEIR OWN, as I suspect many /. readers know from their own childhood interests.
Plenty of science and research on education has been done and continues to be done. Some are applying this wisdom but the USA is not. It IS political and it's not actually the unions or lazy old teachers. I also know some of what actually goes on in that area as well. I personally know somebody in political system who is among a group who's goal is to ruin public education for the long term goal of completely recreating it along their ideals. Why ruin it? It is simple, people love public education so it has to be more than just attacked, it has to be made less lovable.