Your points reminds me of some comments made by one of my former professors at Appalachian State, Dr. Harold O’Bryant who, along with Dr. Mike Stone (also at ASU for years), co-wrote the book “Weight Training: A Scientific Approach”. He was critical of the current system of educating PE teachers. His point was that since most PE teachers get into the field, at least in part, to coach, why was there not a proper, practical coaching education curriculum established for these people? He pointed out the dangers of having unqualified coaches working with athletes.
He fully supported that for sure the PE teacher needed to know how to properly teach their courses and write lesson plans but that some time should be devoted within the education to teach these same people how to coach. While there may be some of this occurring nationally, I’d say it’s far from widespread. Most of their classes dealt with pedagogy and lesson plans yet very little to do with coaching/training.