Earlier quoted context omitted.
The problem is, there doesn't seem to be much elasticity in the size of the market. Books are rivalrous goods: an hour spent reading book A is an hour you can't spend reading book B, or watching a movie. And a lot of people prefer to watch movies -- or play computer games, or kick a ball around -- to reading books for recreation. Unless we can work out how to convince more people that reading for pleasure is fun then…
Its an error to assume folks actually READ the books they buy. I have a tall stack of books I'll get around to reading. I paid for them all of course.
I also have a physical stack of unread books, which I'll probably never get around to read now that I have a Kindle, created mostly due to impulse buying on bookstores. Some I also bought again digitally.
I'm now growing my virtual kindle queue, faster than I can read, but with a different approach: I added all my wishlist authors (including cstross, incidentally) to ereaderiq, which notifies me of price drops, and buy 1.99 daily deals or similar range. So far I got very good deals on good titles of Arthur Clarke, Kurt Vonnegut, Neal Stephenson, William Gibson and so on.
So, again, anecdotally, I might buy things that I'll never read, but the amount of titles that I haven't read is bigger than my daily reading time, and after a certain quality threshold, titles seem mostly interchangeable.
I'd guess the best price point is the one just on 'impulse buy'.