Schlock books only take a few months to publish. High quality nonfiction books -- those that are thoroughly researched, well thought-out, concisely written, ruthlessly edited, and carefully proofread -- take typically one or two years from the time the author completes the writing of the manuscript.
Few tasks can be done in parallel. Most tasks need to be done serially. The book's graphic designer shouldn't do her job until the manuscript has been completely proofread and edited. The proofreader shouldn't proofread until the editors are completely satisfied. And so forth all the way back to the initial concept stage which often is five or more years before you actually see the book in a bookstore.
I would expect --based on my own experience as an author and as a former editor and publications manager -- that a book as revolutionary as
The Starch Solution -- requires meticulous technical review by at least a few experts. Each reviewer might need months to slowly review the book for the cogency of its argument and to challenge its footnotes or bibliography.
Thousands of hours go into producing a high-quality book. And it only costs us a few dollars. That is worth waiting for.
My own, most recent book,
The Power and the Glory (
http://www.reasonversusmysticism.com/), took me 12 years to research, outline, write, and edit (in five cycles). Then it took a year for technical review (by academics) and a year and a half to go through the publisher's process of editing (three editors), proofreading, and graphic design. Even then, with all that help, one alert reader has now found about 10 minor errors (e.g., "Patterson" in one place, but "Paterson" in another place). I am sure there are more errors waiting to be discovered.
Striving for quality takes time. The end result is worth it.