Tess Gerritsen has an interesting post up about purchased bookspace over at her weblog. Publishers do pay for space on the front tables at most major chain booksellers, and yet often those books never make it to their premium spaces.
Why? Going by my experience as a bookseller, the individual managers and/or floor workers likely:
1) ignored the weekly sales sheet sent down telling them to put TG's book up front and instead stacked what they wanted there.
2) didn't change out the front table because they were too busy (generally, understaffed and chained to the register, which means stocking after store hours.)*
3) had no room for the book because last week's books didn't move and decided to shelve the new arrivals.*
One of my managers completely ignored the weekly sales sheet unless there was a regional scheduled to drop in that week. She knew her customers were mostly romance readers, and devoted half her front space to romance novels instead of the usual bestsellers and major pushes. One time we stayed until 2 am and practically had to tear apart and reshelve half the store to get it according to sales plan because our manager got wind of a surprise visit by upper management the next morning (which is why our manager never got written up for not having the store according to plan. She had excellent spies.)
If a purchased-space book shipment is late? Those books never touch a tabletop. If the book is overshipped, a manager might get creative with stacking, but generally they shove the excess copies back in the store room. Jackie Collins does not want to know how many times a hundred copies of her novel sat showing their pretty leopard-skin patterned book jackets to nothing more than the employee coffee maker and concrete walls.
Also, chain store employees who work the floor and are not into reading view books the same way a grocery store bag boy views sacks of potatoes. One of the youngsters who stocked with me complained about having to unpack, move and stack hardcovers because of their weight. When I switched her to paperbacks, she bitched because there were too many authors' names to put in order. Of course, she found reciting the alphabet properly kind of a challenge, too.
This is not to say all booksellers are ignorant apes who toss our books wherever they like. On the contrary; most book store managers I've met are remarkable readers and genuinely interested in the business of bookselling. Some of their best employees are the same, and can hand sell books at the rate of ten to twenty an hour. I loved working the floor myself; talking with customers and hunting down a good read for them was a lot more fun than stacking the front table.
Yeah, well, maybe make that reason #4....
*Note on #2 and #3: from a bookseller's perspective, shelving is always easier than displaying or tabling. You can shove books on the store shelves aside to make room for new arrivals. This opposed to removing last week's books from the front table, carting them, and reshelving or store-rooming them before you can haul out and table the new books. Purchased-space books are double the work.