Well, we agree that they are "completely different books." However, Mark Fuhrman is not a "P.I.," and Cheryl Ford's "CV in the medical field" is neither extensive enough, nor impressive enough, to sell books.
But that's not the reason that her book will not be "on bookshelves." It won't be sold in bookstores and through the big online booksellers because she doesn't have a publisher in the traditional sense. Her book is being "self-published" (vanity published; she's paying to publish it), and that takes it out of the pipeline for bookstore/bookseller placement.
Hundreds of thousands of books are vanity-published every year...it's not a "bad thing." Vanity publishing has been going on for well over a hundred years, as would-be "authors" are willing to pay to see their works in print. With the advent of the internet and e-books, it's a growing and lucrative business (at least for the vanity publishers, not the authors). Very few vanity-published books find the success that motivates a regular publisher to option them (and thus move them into bookstores). Personally, I'd be pleasantly surprised to see Cheryl and Jan's book optioned. However, the likelihood of that is very small. While it would be normal for Cheryl and Jan to pay for, and then consign, a small supply of their book to a few willing local boutiques, the chances of seeing the Ford/Craddock book "on bookshelves" (meaning in places like Borders, B&N, or even WalMart's books secion) is slim to none.
Cheryl Ford's book is going to be on the shelves. I wouldn't belabor the point if I didn't know it for a fact. When her book is out, I'm sure someone will post where it can be purchased.