" Ultimately what differentiates the books come down to the explanation of the concepts, more specifically the artist's personal take on the techniques." - I think you really hit the nail on the head on that one. It's not the technique, it's the presentation.
Also, didn't think about a possible ghostwriter but that seems plausible.
On another note, if I want to support your blog & channel do I have to click on your affiliated link every time I shop or does it "remembers" for a month or something?