Yes, I completely agree with you both, and if an international effort ever is undertaken to genuinely attempt to preserve all of the most important information for recovering civilisation it would certainly need to include copious diagrams and graphics, and perhaps animations and videos too. I discuss this very topic on the
'How To' webpage. But at the end of the day, 'The Knowledge' is a popular science book about the underlying principles of science and technology of our world, and not really intended for post-apocalyptic survivors. In this way, the book is necessarily limited in certain ways - to only around 300 pages, for example, and people wouldn't really want to wade through hundreds of technical drawings.