Today I read yet another book review that lamented the author's dry style in an otherwise excellent book, and asked mournfully "Where was the editor on this?" The short answer is that editors -- even the most gifted of them -- don't re-write authors' books. Not only is it not their jobs, it can't be. Can you imagine how much time it would take to laboriously re-write chapter after chapter for an author who would then immediately "fix" it all back to the terrible way it was, because he or she lacks the fundamental literary ear to recongize superior writing? This sort of back-and-forth can take months if not years, and sharp editors learn early in their careers not to engage in that sort of unproductive labor.
There are indeed line editors available to authors for a fee, and some of them are excellent. A few are retired publishing house editors who earn a fine post-career income doctoring books. But anyone good will charge a minimum of around $10,000 for a 100,000-word book, and will be worth every penny. And once again, there is nothing to stop a determined author with a tin ear from "fixing" half of it back again, simply because clunky writers can't tell the difference between their prose and the professonal's.
Frequently when reviewers ask "Where was the editor," what they should really ask is "Why didn't this author hire a ghostwriter?" Ghostwriters are the unsung heroes of readable literature, and they rarely get their due either in credit or in pay. They deserve much more of both.