All of the points you express are understandable and in general I agree. But as others here have expressed, teaching can be a learning experience for you as well. There are many things you may know on a certain level, but when you try to explain it to someone else you are forced to dissect the concept (sort of like concept bunkai) and often this gives you some revelation,
viewpoint or understanding of the thing you thought you knew, but in a way you didn't know you knew it. It challenges you to see things from a certain angle you may not have previously done and thus see things you've taken for granted over the years. Teaching can also keep your techniques finely tuned as you try extra hard to provide the students a good example. I see teaching as 50% for the student's benefit and 50% for my own.
Iāve heard this idea before but it suggests that a practitioner is a mindless automaton just going through the motions of repetition. That
will be the case for some admittedly, but Iād suggest most of us do
think deeply as we practise and for the benefit of our own progress. During these sessions we may hardly break into a sweat because weāre thinking, āI canāt do this because because my centre of gravity is outside my base
ā¦.I need to enlarge my base slightly by perhaps pulling my knee around to
this point. But thatās really difficult due to the high coefficient of friction on that knee unlessā¦
ā¦I engage my core, specifically, hip flexors, and shift my weight more onto the other knee and BANG! I can do it. Oh quickā¦let me try that againā¦.YES! Let me write it down!!ā Weāre
active learners and although we might not articulate these ideas for the purposes of teaching, we still go through the same process.
In my experience, many teachers are insufficiently verbally articulate to get these subtleties across or unable to arrange their thoughts in a logical progression of ideas to allow the learner to perform a technique. These tend to be the types who advocate endless repetition from their students rather than analysis/repetition. The martial arts are full of such teachers, unfortunately.