I think I was the first one who brought up electricians, but my only point was to illustrate that in many professions, if someone who is an expert chooses to show someone else how to do something properly in that field, that apprentice should be able to make it work.
Given that this discussion was about traders offering books and videos, and hence the experts in this example, it should follow that some apprentices should have been able to trade profitably as has been taught. All we seem to have though are others saying they take certain ideas from some of this material, but that none actually in fact trade like the book or video would imply.
The implication of this once again would be that if an electrician says this is how you wire a receptacle, this is the correct wire to use and this is how you attach it, you really shouldn't stray from this procedure. Of course trading is much less rigid, and there isn't government code that specifies how it should be done, but I hope that my original point is clear.