I respect (most of) your views on HE, and I would agree that one-to-one teaching is a good place to start. One-to-one by someone qualified would be better, but you wouldn't get that at school anyway and you know your own child better than anyone else.
Where I part company with you is where you say "most schooled children of involved, interested parents do most of their learning out of school anyway". That would render my job useless. They may learn most about other things from their parents - a wider general knowledge, for example, or extra-curricular experiences, but not curriculum based stuff, no - most of that comes from teachers, it's what we do. (Apart from in your case, where you do that. But you said most schooled children.)
Then this bit - "School, IMO, only really benefits children of parents who aren't at all interested in them, never take them places, don't read them books, don't talk to them etc."
If that were true, why would I bother teaching at all, unless I taught in a truly deprived area where parents didn't care?
Some of the children I teach are deprived, and I enjoy helping them to achieve - but I also enjoy teaching other children with full support from their parents.