1. There is no magic - there has to be local muscle involved, and yet the involvement of said local muscle is quantitatively different if other parts of the body are being used in an optimal manner.
I agree with the first part of this. I don't understand part of this- "involvement of said local muscle is quantitatively different if other parts of the body are being used in an optimal matter". If by quantitatively different, you mean that local muscle groups don't have to work as hard to deal with a force if the other parts of the body are being used in an optimal manner. I agree also. I don't know why you added the "and yet". I also think you will find many athletic coaches in total agreement with this.
2. In my experience there are not so many good athletes who are doing similar things really. What is perfect technique? If you are good enough to beat your competition, then what is the point of improving further? The number of people who *really* pursue this is not so large I suspect.
Your experience is always a factor in these things. I have been around a lot of professional and serious amateur fighters. In my experience correct body use, much like you describe above is the norm.
I believe the second part of this is a philosophical statement, "if you are good enough to beat your competition, then what is the point of improving further?" From a competitors stand point, some may have this opinion. From a coaches stand point, you always drive your athletes to higher standards, nothing is ever enough. I would suspect among the best athletes you'll find this same "never good enough" attitude as well. This is why they are the best. Either way it's a philosophical point, and really doesn't have to do with the body use itself.