The final section setups up a contrast between the and now that is meant to help motivate you to read the book. I don't see the section as particularly weak, i

The final section setups up a contrast between the and now that is meant to help motivate you to read the book. I don't see the section as particularly weak, it does exactly what it supposed to and it's argument is sufficiently strong for that purpose. I would note that while you complained about the argument being weak, you didn't actually make any effort to edispute any of it. If you found the topic interesting and wanted a deeper study of the topic, then thats great go do some research, I doubt nobody else has researched or written about it. Complaining that a book review isn't a scholarly article or a full essay isn't actually gonna get you any deeper understanding of the topic.