cb, I often see you weigh in on this topic. Here is my "take" on it. I will be the first to say that there are many truly good sports performers that don't do it "by the book". It doesn't matter what sport -- archery, golf, tennis, you name it. I for one shot for many years as a self taught archer. I had no one to help or coach me. In fact, I was 40 years old before I even met another person that shot a bow seriously. Up to that point the folks I knew were "playing bows and arrows" once in a while.
Most of us, who are trying to really help new comers to the sport, need a structured system to help them get started. To help them use the best muscle groups for the shot, to prevent injury in the long term and to help them enjoy a higher and faster success rate than is or was possible with the self taught system.
Who taught the Indians/Mongols/English/Samuri archers??? I do not know! Did they use NTS form? I don't know (probably not)! Were they good (by what standard)? I don't know! Were they able to do what they needed? Without a doubt!
I am reminded of the musical "The Music Man". Professor Harold Gray came to town and started a band with the "think system". He said that you could whistle a tune without knowing music. So you should be able to play it on an instrument. Welllll, yes you can. And some protegies can play anything they hear on a piano (some unkindly people call those folks "idiot savants"). The human is an incredible thing that can adapt and over come and make things work. But...
For most folks, having a structure and pattern to follow when learning, shortens the learning curve and usually leads to better/higher performance levels at a faster pace than just stumbling through the process and hoping that the think system will take them to the level that they will be happy with.
Frankly, I tell my students that if they will work on form and blank bale shooting for the first two months, I'll have them hitting the target in three. Hitting the target is the easy part, being able to do it more than once in a while takes a repeatable and correctable form.
Again, is this the only way? NOOOO!!!! It is just a consistent way to do the best for the beginner or to improve an experienced archer that wants to shoot better than he/she is currently shooting.
As far as I'm concerned we CANNOT put too much emphasis on form!!!!!