"So unless an author spends their whole advance on P.R. or has enough disposable income to do their own nationwide blitz, they're screwed?"
Where did this come from?. Let me make it clear. You have to do the work or very little will happen because no one cares as much about your book as you do. Unless you don't care about actually selling copies of your book. Then you can sit on your hands (or your ass).
No one can sell your book as well as you can. You can, of course, hire "professionals" (not like agents - we work on commision, unlike any other professional in publishing other than authors, who work on spec at the beginning) who you can pay, but they won't go the extra mile or make the extra call. If you write the personal letter to the reviewer and it actually gets to them, you might get a call and an interview. If you call the bookstore ("I'm a local author and I shop there all the time..."), you might get a reading. Otherwise, the books will be mailed to names on a list and they will compete with every other first novel and how-to book published in the same month, and you just won't break out.
I know. My first book, which I sat on my hands for expecting my NY publisher to do their job, was featured in Family Circle, Woman's Day, USA Today and even The Wall Street Journal, and it sold less than 2000 copies (and I think a quarter of them was from signings I arranged myself). If I had gotten some quotes, had a blog, was in a network, etc., it would have sold at least 5 times that amount.
My second book, for which I did a number of conferences, got great reviews, asked people to write Amazon reviews for, ect., has sold over 13,000 copies.
You also have to get your own quotes. Your editor and your agent are too busy doing other things for you to advance you career. You have to set up your own website - we're not going to do it for you or pay for you to get someone else to do it. Same thing for your blog.
Nowhere in my list of what an author has to do did I say anyting about hiring a P.R. agency. In my experience, unless you really have extra money, you'd be better to come up with your own P.R. plan or hire college students to make the calls for you. The book publisher's p.r. department kind of runs on automatic. But you have to put aside the time, make the commitment and follow-through.
The only reason to hire a big P.R. firm is to get on national TV (Oprah and Larry King) and in national magazines. They have the contacts and you don't. But if your book doesn't have a snow ball's chance in hell of actually getting on one of those shows, you are wasting your money. Be realistic. No amount of money spent on p.r. is going to make an Oprah book out of a sow's ear.
The average book can get more coverage and reviews with the work and networking you can do than anything a professional p.r. agency or the publishers' p.r. agency is going to do for you.
Have a great weekend.
I expect to continue this train of thought next week, as I've received a ton of comments and questions.