Someone was asking me about publishing industry changes and I don't even know the half of it because everything has changed since I started, and I obviously don't know even half the story. But here's my ill-informed perspective, based on experience, observation, and talking to a few people in the know. The major change that I see now is that most agents don't even bother to respond to you, even if they ASK to see your manuscript. And the publishers are even worse, because they're doing the same thing to agents. I believe everybody is running scared both because of the economy and the rapid changes in the industry and technology that are blurring the definition of "published" and even the chain stores aren't sure how to deal with it.
Bookstore orders are roughly determined at about the time the publisher offers a contract--if the publisher pays you $10k it's going to print enough (and pretty much ONLY enough) copies to make its money back, and the bookstores see that figure and judge the publisher's amount of advertising (which will be none for practically any book below bestseller) and pretty much pick a "typical" number for that publisher's midlist sales in that particular genre. Say, Harlequin Hottie line sells 8 titles per store, so they will order 8 copies NO MATTER who the author is. Once your own name is out there for a couple of books, they go entirely on that data, which is why you need to do as many signings and promo events as possible in the three months after your book comes out. Very rarely does anyone suddenly get a big swell in sales, usually the opposite happens, unless you get great word of mouth or get real lucky.
There's really not much you can do besides all you can! Unfortunately this Amway method puts all the onus on the author, who can least afford the time and cost and has not much money to gain, with the real threat of never being able to sell another book if your sales tank (unless you get a pen name). Cheers. That's not to say I've been eating sour grapes. Authors are obviously still selling books and stores are still open, so somebody's doing something right somewhere. And I believe every great book--and most good ones--will eventually find a proper home.
The good news is, all that has not a lot to do with the real reason for writing--to express, to scream, to run naked, to giggle, to survive.