I think you raise some good points.
However, it seems to me that teaching enthusiastic students with lots of parental support is comparatively easy. I dare say, had I had the Internet as a student, I would have learned more on my own than in a classroom setting, likely only needing periodic guidance. A good part of my K-12 education was waiting around to be spoonfed the next morsel of info, especially once I had the basics down (like by the 5th grade).
Does one really need an education degree, periodic seminars, tenure, early retirement, etc. to teach the high end students? The “work” of teaching - where we need the best and brightest dedicated creative professionals - is in the difficult kids in the bad situations.
Their are fundamentally three tiers of students:
The better students are not taught so much as guided and engaged. The ones in the middle are taught in the conventional sense. The ones at the bottom are warehoused until they’re “done”—if you’re lucky, they learn enough of the three Rs to function in society.
From a student perspective, much of this is self selection. A bad teacher can potentially cause a student to go from an upper tier to a lower one. Conversely, a good teacher can cause a bad student to go from a lower tier to a higher one. But these are exceptions to the rule.