One thing I am noticing in your discussions, is teachers deviating from the way they were actually taught! Some of this may be the fault of various editors and publishers though.
The teachers have to because of the era we live, they have to adapt. When i was taught back in early 70s, i had my main teacher,and some other secondary tutors, and that was it. What they said was the truth because i had no other way to check it.
All the book available were music books, all the players and teachers were all musicians.
There was no internet, no mags, no video, no tapes as such just vinyl the books and the teachers.
We had no outside source to contradict what we were being taught, we learned in class and in order of information as seen to be relevant. Often if someone got slow they were separated so they did not get a musical idea or teaching they were not reafy for.
The tutor would bring them up to speed so they could rejoin the class, the tutor was only allowed to deal with what the teacher had told him to do. They would not answer questions about anything other than what they were told to do and offered no opinions on your teaching to date, it was not for them to question an others method.
Now a days this system is impossible, the freedom of information and the ideas that allow players to get ahead of themselves or try and understand ideas to soon without foundation is rife and that is a problem for players of a certain attitude.
The true musician is still there.
This influx of distracting information, and players who seek it, is a way for those who would never really have chosen music anyway, so it is their problem they create and need to solve, not an education systems one, that is why they support these ideas because they give them the quick short term fix before they move to something else.
Those that take music serious will always find away to learn correct.