(Oh, very quickly, the idea that if your book isn't a bestseller, it gets whisked away to the backroom at the end of the month to suffer a gloomy fate is kind of funny, because generally speaking even if it is a bestseller, it gets whisked away to the backroom at the end of the month to suffer etc.
There is always a bestselling paperback or dozen, and there are always placement dollars for those books that necessitate the previous month's bestseller's removal from prime retail real estate. I covered this a couple of years ago, in a) returns and b) promotion – but it bears some (small) repetition here: To keep multiple pockets of a novel on display you need to have a minimum number of books in stock. Those books are essentially filler. You don't really expect them to sell; you expect them to be there so that the book has prominent display (which was paid for by the publishers)(unless head office didn't order enough for that display, which does happen, and boy would I be furious if I had paid money for placement).
Given the space for backlist, you are unlikely to keep all of those books in your store when you can always reorder should they sell out, so you strip them and return the covers. The timing for hardcovers used to be longer, but there is so much published in hardcover these days that hardcovers do get pushed along, just like everything else.
That was this post's digression.)
I think that the notion of "bestseller or bust" comes partly from writers and agents and the stories that arise from midlist sales.
By this point you've all heard of authors whose books were published to low numbers, and whose subsequent books, thanks to the vagaries of computer ordering, were published at even lower numbers in a kind of downward spiral, the result of which was that said authors were frequently dropped by their publishers. These stories are by and large true. On an individual level, your book needs to develop legs quickly – by legs, I mean needs to sell out and be reordered fast. At one point twenty years ago, no one expected this kind of instant momentum, but twenty years ago is just that.
Ergo, if you personally are not a bestseller, your book(s) die and you fade from view. Building this up into a situation in which "bestseller or bust" seems the rule is not that hard to do, and I believe that that is what's being done in this case – but from a publishing perspective, it's not mathematically accurate.
Because: While the individual midlist authors may come and go because of the way orders & numbers work overall, the fact is that the sales numbers for the midlist in general are not actually dependent on specific authors. When one midlist author has been let go, another has been found; the publisher soldiers on, even if individual authors pause by the road-side to take stock. The publishers can make money on a reasonable midlist populated by, well, midlist writers; they don't need to spend 9 billion dollars chasing the next Harry Potter. And for the most part, they don't.
And even in the event that an author does attain Bestseller status, you needn't look very far to find one who was bought as a midlist author – Rowling, for instance, with her first UK publisher.
Okay, I feel a pressing need to digress again. Because I think a point should be made about sales numbers. It's not necessarily the numeric value of a single title's sale that causes excitement among sales reps.
Take two midlist first novels. One has a laydown of 25K copies in mass market. The book eventually has a decent sellthrough, but in the end, the second book will not necessarily be ordered in the first book's initial numbers, so a downward or static trend is inevitable. But the other book… well, that book had an initial laydown of only 20K copies. And people are hyped about it. Why?
Ms. Big Chain Buyer, orders 20,000 copies of the second First Novel. Of those 20,000 copies, an absolute minimum – regardless – of 3000 books will be returned as overstock, and this would in general be considered a fabulous sell through. Why? Because what will generally happen in this case is that most of your outlets will have sold out of the book, but owing to geography or shelving, etc., some won't, and will duly return them.
If both authors are in this position, so far so good. However…
IF the outlets that do sell out manage to sell out quickly enough and IF people come in and special order the First Novel, etc., the book will be reordered (I leave off the cases in which the book is underprinted and is in a 2nd or 3rd printing before the book even hits the shelf, generalizing for the sake of simplicity). Most big houses can resupply the book in 2 or 3 days if they have any in stock. So while my initial laydown was 20,000, if the book actually sold really well and was reordered frequently, I might end up with orders for 25,000, and returns of 5,000 in the first reporting period.
That 25% figure that gets tacked on in reorders will influence the number of books BCB will order by that author when the Second Novel is offered. And everyone in-house knows this. The next laydown for the author's second novel is likely to be higher than the first (say, 30K conservatively), with backlist resoliciting of the first book.
This is, of course, momentum. This is what people, in the end, really want to see. You don't need to be selling 300k copies to generate that level of excitement.