I love how the books that need the least promotion get the most. I will use as an example, say Harry Potter 7. The book is eagerly awaited. There are fan sites, "what will happen next" books, and all sorts of private parties. The book is getting tons of hype from the amateurs. And still Scholastic and the big chains are spending a ton of money. There are all kinds of prizes being given out. Most stores are planning huge release parties. (My favorite so far is Bookpeople, here in Austin, that's going to have the entire Austin Symphony Orchestra out doing something.) Admittedly release parties happen for other books, my store's having one for Riordian's Titan's Curse in May, but they aren't at midnight (overtime hours) and they don't require most of the staff to attend as crowd control. And Amazon is now sponsoring a contest for the Harryest city in the country. Basically Amazon will donate $5000 to a charity of Amazon's choice in the city with more than 500 people that preorders the most books. When will the madness stop? I plan to read HP7 because book 6 ended in such a nice unresolved way. Would I have done it without the publicity blitz? Yes. And if the book ends up being awful (which I doubt) then won't all that money look like a waste. Preorders are great, but nothing can save a book if word-of-mouth says it's awful.
Still, if I was a midlist author watching all this money being spent on a book that's doomed to be a success, I think I would be, at the very least, depressed.