This just flashed into my mind, and since its feeling pretty lonely in there, I thought I'd let it out here.
In manufacturing (pharmaceuticals come to mind, too, but that's a totally different scenario with buzzards in the trees), prices start high to cover the cost of research and initial manufacturing. Naturally, the prices stay high as long as someone else doesn't reverse-engineer the product, but for the most part, the prices eventually come down (except, of course, the pharmaceuticals which people really NEED within the borders of the US--the same drugs somehow are magically cheaper outside the U.S.).
The thing that occurred to me is that perhaps publishing on a book-by-book basis isn't much different. The research might be the authoring, and the publisher might be the manufacturer with the retooling and advertising (and other) costs.
From what I have read in the forums, it appears that like many researchers in other industries, not-Rawlings-or-King authors get a pittance at best and the "Company" gets the rest. Indeed, much "research" cost is lost because every attempt is not a success in any industry, and that cost must be made up by the successes.
On top of that, unlike every other industry, books can't be reverse-engineered and produced by a competitor to bring down the price. The closest the book industry comes to that is the proliferation of used book stores.
So I guess I'm just saying that viewed from that perspective, I can see the reasoning behind the hb pricing which is the initial manufacturing release -- just like the initial release of any product, and pb pricing reflects the same price reductions you see after a year in any other industry.
A simple(-minded, perhaps) example is DVD movie releases. Harry is around $14 (US) right now, but the 5 previous movies are all around $7. It doesn't cost any more to create the new DVD than it does a year from now, but the market will support it, and a year later people like me buy the $5 edition which plays just as well.
This may or may not be presented as well as it sounds in my head, but now that you are reading it, its no longer alone inside there.