Let's say John Q. Public enters a bookstore intending to buy a book. Some people believe that John intends to buy a certain book, x, and if he sees something else he loves (as a result of co-op placement, let's say), he'll buy that new book in addition to x. I'll grant that this is probably the case for consumers who are more or less unaffected by the recession, or those who have enough money to pretend not to be.
With regard to the majority of consumers, however, I disagree with this model. I believe that, explicitly or implicitly, John enters the bookstore with the idea of spending x dollars on (a) book(s), and should he find something he strongly prefers to his original target (e.g. The Lost Symbol), he's going to buy that book instead of what he was originally going to buy. This sounds counter-intuitive, I know, but hear me out.
1. Dan Brown has a phenomenal amount of marketing and publicity, meaning he's going to be most consumers' initial target anyway. This is cheating, I know, but it's true: the amount of attention he gets before on-sale almost guarantees that he's going to be the number one priority for many consumers come September. So, before we even consider the number of people he "converts" in-store, he's already converted millions of people who have yet to enter a Barnes & Noble or Borders. You know when people say "If you buy one hardcover this season, buy x?" Well, in this case, x = The Lost Symbol.
2. The national chains will be more focused on Dan Brown than anything else. This means that they'll be subtracting space from other titles to allocate toward The Lost Symbol. More space for Brown per store means a higher likelihood that consumers will purchase his book over another.
3. Hardcovers are expensive. The average hardcover costs around $25.00. If you walk into a B&N intending to buy the new Charlaine Harris and instead discover a massive shrine to Dan Brown, will you buy The Lost Symbol? I think so. Will you buy both? Probably not; that's $50.00.
4. The numbers seem to bear it out. Arsen notes that, despite phenomenal sales for Dan Brown's last book, overall sales were only very slightly up at his store; sales for The Da Vinci Code replaced existing sales rather than adding to them. Individual consumers have limited amounts of capital, and when they have the option of buying one book or another, they seem to be more likely to buy their preferred novel over buying both. And when Dan Brown's out, his book is preferred almost by default.
Sure, pre-ordering allows consumers to pay now and pick up in September, and for this reason the major chains (as mentioned in yesterdays comments) are really pushing pre-orders. It should be noted, however, that this doesn't affect the total amount of disposable income any given consumer has, and that a pre-order for The Lost Symbol is still competing against other fall pre-orders; nothing has really changed.
If your novel is coming out this fall, then, you'll be facing some stiff competition; to be perfectly honest, I think you can expect to see slightly lower sales numbers for your title as a result of the Dan Brown colossus.
You tell me, though: do you think this is an accurate description of your own behavior as a consumer? Why or why not?