Your point is well taken. I was not arguing against it but showing that it is important for an instructor to be able to demonstrate the skills they are teaching. If they can't because they aren't compentent enough that is the fault of the management for letting them teach beyond their skills. If, on the other hand, they are showboating and skiing above the ability they are trying to teach, they are simply not good instructors, no matter how well they can ski.
It is not a huge issue for a coach or instructor to be able to demonstrate something perfectly. What is important is they know how to break it down and explain it to someone who is learning it. I have worked with instructors that can demonstrate something perfectly. Yet they did not know how to break down the movements so a beginner learning them knew what was going on to make those movements happen. This is where I see a break down in PSIA. The majority of PSIA clinics and so forth I did put way to much emphasis on improving the instructors skiing. This is what has contributed to the very robotic ski style of instructors. The four years I taught full time my director gave me permission to not go to the weekly mandatory clinics. The reason is all the clinics did was try to change how I skied. I asked several times how it was going to make me a better instructor and they had no answer for me. I would have attended the clinics no questions asked if they actually taught me something I was going use on the hill in my lessons. I have experienced this at more than one resorts and my sister experienced the same at other resorts also.
There is a old saying that I think has a lot of truth to it. Those that can, do. Those that can't, teach.