The author mentions at the start the difficulty of treating the topic, when so much relevant information is not well known. Therefore, there is a lot of information given that makes the focus feel less sharp.
The information it covers is important, especially looking at the conflicts between the ideal and the practical, and how easy it is to not realize when more is possible when it conflicts with what you believe you know.
There aren't any real solutions to that, except that perhaps it is best to realize that constant correction is needed, and accept that from the start. Discouraging, perhaps, but perhaps less discouraging than being sure that you can get it right and being disappointed.