Definitely a book that would never be finished and a book that probably could be over a thousand pages if it covered everything.
It's easy enough to get people started and I can only assume laziness or lack of interest in doing a layout, is the reason more people haven't at least done the layout in the book and gone on to produce another layout.
It's like cooking, I can understand why people wouldn't attempt doing a layout or cooking something, if there was no instruction, because it would be difficult for many people to know where to start. But doing the layout in the book, is pretty much like a recipe book and following the instructions to cook it.
Anyone who does complete the layout, have the knowledge, that if they were the only person interested in doing a machine or the only person left in FME, that they could still produce it as long as the rom where available.