I'm afraid I'm too intellectually lazy to even be able
to think of all the things you brought up but I'll try
"when one reads the books, they say pretty much what others have previously said and the subtleties (the real secret?) of what makes their swings elite is missing."
I agree completely with that. I may have read close to
every instruction book ever written.
Now, however, when
new ones come out I have strong resistance to them and it
takes a really cagey teaser to get me to bite. And when
I do surrender and buy the new one I am always disappointed
on most levels. It seems I already know everything that
anybody else in the universe knows about the golf swing
but I still can't shoot par. I am ready to concede that
in the case of golf, knowledge is NOT power.