It's quite silly to suggest that a book could be made more "concise" by omitting what appear to be some of its central theses. (This is an extract from the first few paragraphs). It's also silly to expect the introduction of a book to provide detailed arguments in favor of those theses. If you want to evaluate the argumentative rigor of the book then you'll have to
read the book, which presumably goes into more detail in subsequent pages.
You really don't seem able to take a book on its own terms. This book wasn't written to give you personally exactly what you want from a book. Just because you want to read pages of dense logical argumentation in flat prose doesn't mean that you can fault every author who writes a different kind of book.