<<That presumes they have a reputation for honesty.>>
Nope. It presumes they DON'T have a reputation for dishonesty.
<< And it also assumes that there are other book deals in the works.>>
Ha. We have a published writer in the family. I personally proof-read the MS before they went to her editor. Let me tell you, every writer is always looking ahead to his or her next book deal. None of them intends to be a one-hit wonder.
<<Look it isn't like Schecter is a well known author. Remember he was hired by the third largest contributor to "progressive" causes to write the book in the first place.>>
Let me suggest a little experiment to you. Place a two-line classified ad in the biggest regional newspaper in your end of the state, "Writers wanted for new publication, no experience necessary, mail resume and samples to P.O. Box 9999, Athens, Ga." Along with the (literally) hundreds of unpublished wannabes, you will get dozens of applications from published writers, some of them undoubtedly recognized by you.
My point being, NOBODY with good money to spend on a writer has any need to settle for some unpublished, untalented schmuck because good writers, published writers, are a dime a dozen. If Schechter was hired to write a book, you can bet your ass he was a writer of some ability, not necessarily a James Joyce or a Dostoyevsky, but somebody who knows how to write and how to turn in a product on deadline, has proven this in the past, and is not looking to publish his last work at this point in time.