I suppose I must just be the most naive amateur writer in the world, because I thought that at least some editing of books went on at professional publishers. I knew that very successful authors don't get edited as much anymore--as witness Anne McCaffrey's lates few books and the horrible first chapter of Halfblood Prince. Somebody should have taken a stick to J. K. Rowling for the awful technique stuff in that first chapter, but it's pretty clear that they published what she sent them.
Now, from looking at the reviews of this book and some excerpts from it, it appears that, by and large, the only editing your book is likely to get is the editing you do on it yourself. I don't know that this is true across the board, but it is apparently true for many.
I'm pretty horrified. On the one hand, editing your book yourself can only teach you to become a better writer. The idea that there might be no one at the publishing house who would look your book over aside from your agent is a bit scary, though. It helps to have a pair of fresh eyes look at your book--fresh eyes of people who aren't your beta-readers or yorr friens or family, people who can tell you, "This needs to go," or "This needs to be changed."
I will be very interested to read this book when it arrives.