1) The book's cover price. This is set by the publisher after intricate calculations that may allow the publisher to make some money.
2) The book's cover art. Cover art is designed by art departments at the publisher's with input from marketing and editorial, but none to little from writers.
3) The book's publication date: This is set by the publisher in hopes of finding the sweet spot for that book where it will show well against the competition (or to protect a similar book from the same publisher.)
4) The book's actual appearance in a store or as a download. This is decided by the bookseller, who may or may not pay any attention to the publisher's stated release date. For books sold through multiple outlets (most conventionally published books) each bookseller makes the decision when to sell the book.
A) This means that Store A may order half as many copies as Store B, and put them on sale earlier or later than Store B. The writer did not have a conspiracy to make you buy at one store or the other. The stores (or corporations running dozens of stores) made the decision.
B) This also means that a bookseller like Amazon can completely ignore the publisher's release date for paper copies and insist (for whatever purpose who knows?) on withholding downloads to Kindle or other e-readers.
The very talented Seanan McGuire, for instance, is stuck right now in exactly this situation. Amazon decided to deliver the paper copies of her new book to those who'd pre-ordered two whole weeks before the release date...but withheld the e-copies from those who'd preordered it for their Kindle. Naturally, Kindle readers were angry. But they were angry with McGuire, when they should have been angry with Amazon. McGuire didn't even know (until abusive emails started pouring into her inbox) that Amazon had wrongfully shipped the hard copies or refused to release the e-books. Not her fault. Yet...she got piled on, with accusations that she was trying to force people to buy the hard copy out of greed. And she is justifiably upset and hurt that she was blamed for something she didn't do, especially in the abusive terms people used..
She had nothing to do with it. She had nothing to do with Barnes & Noble, who held out for a few days, deciding that they'd sell the books they had in the store (rather than lose more market share to Amazon.) That wasn't her decision; it was B&N's decision. She and her agent and her publisher and the distributor haven't been able to budge Amazon a millimeter from what was a stupid decision on Amazon's part, guaranteed to make customers angry.
So...why aren't these customers angry with Amazon? Why are they angry with McGuire? It makes no sense. It makes no sense that people would automatically blame the writer without even asking who made that decision. It's obvious to other writers that the writer doesn't control Amazon's decisions. And it should--after the number of writers who've taken the time to explain over and over--be obvious to those buying books.
But in case it prevents future abusive attacks on some hapless writer, here are some other things
the writer has no control over:
5) The price at which Amazon or other discounting booksellers sell the book. Some of this is contractual between publisher and bookseller; the writer isn't consulted. Amazon, for its part, claims the right to change the price of self-published books at any time, for any reason. It's not the writer trying to game the market: it's Amazon.
6) The quality of paper, printing, and binding. The publisher chooses the printer and binder and attempts quality control, but it's really the responsibility of printer and binder. If you find a chapter of another book upside down in the middle of one you bought...it's not the writer's fault. If the glue on the binding fails...it's not the writer's fault.
7) The book's overall design (size of font, width of margins, "cramped" or "open" appearance). The publisher designs the book.
8) The book's advertising (or lack of.) There again, the publisher decides how much (if any) advertising budget to spend on a given book.
9) The book's placement in the store or on racks in airports (and anywhere else there are still racks of books on sale.)
Bottom line: If you've got a gripe about a book, think before you trash the writer. If you don't like the cover, the print run, the book's design, the quality of the binding, the price, etc. etc. complain to the publisher. If the book's not in your local store, ask the store manager why it's not carried. If it's not carried in an entire chain, gripe at the CEO. If Amazon's not shipping your book or e-book, complain to Amazon.
Complain to the right person. You might get some satisfaction and you'll avoid hurting the innocent.