I haven't had a lesson for years but I remember during that time realizing that many of the instructions my teacher gave me were actually practice suggestions that I could have come up with myself. Either she hadn't credited me with the imagination to come up with my own solutions or only saw it 'her way'. It was a while before I realized these examples were not important points of pedagogy but individual solutions out of many possibilities. This confused the problem with the solution - causing the student to mistake the pointing finger for the moon itself.
'could have' or actually 'had'? It's all too easy to think you could have figured something our for yourself, once you already know it. The thing about practise methods is that a number of them are pretty universally useful. Above all, practise is something that usually needs to be taught, as it rarely falls into place.
There a certainly not many new students who have a good answer, when I ask them how they will practise. Students need to learn a number of approaches that are universal, before they can start using their own minds to find other ways. To claim that a teacher who simply does their job by trying to convey something so important can only see it their way, is really stretching the limits. Leaving a student to find their own way often means finding an inferior way. That's why we learn from teachers. Do you think that Einstein would have got so far, had he been left to deduce every single basic premise of science for himself? Some things are best learned and understood, in order for you to pave your own way. Especially as most of us are not Einsteins (or their musical equivalents).
That's not to say we should never question anything, but progress is most easily furthered when we expand upon foundations of what others have already discovered.