Was shopping at Costco today and naturally we had to hit the book aisle. Well, the section nearest the aisle had Kitty Kelly on the right and Bill Clinton on the left, at least 6-8 rows deep. Then came the various sore loser books like "Bushworld", "Bush is a poopy head", "How Bush sold my kid drugs" and all those. Wedged in between all of those, taking up one measly row was the New York Times NonFiction bestseller for 5 weeks running...."Unfit for Command". Is the entire Costco chain biased, or just the ones up here? A book that outsells Clinton, Kelly and Franken combined gets hidden. I found that almost as funny as the two lezzies standing next to us. One turns to the other and asks "do we need batteries?" I almost bit my tongue in half staying quiet.
Costco has a selling formula that works really well for them...they will sell ANYTHING as long as it makes them money. They assign a fixed value for the space that the item takes and if the item does that amount of business then it stays...otherwise it gets the boot. It could be that you're area has folks who want to buy something else or are uninterested in the book.
I got the above from a business associate that does special packaging for Costco. That's why you always see changes in what is being carried. Each store is responsible for their bottom line and can bring in just about anything from cars to books to boats (which I've seen inside a Costco in the past).