Remember that ebooks are considered a niche market by publishers and that publishers are, by and large, very conservative. Once there are more people purchasing ebooks, and this is where Amazon has done a great service to the community, the prices should come down.
The state of the art in ebooks reminds me of the early days of video distribution where we had competing, mutually exclusive, players, formats, and media. Things have, more or less, settled down and everybody's making money in that venue. It is likely as manufactures of ebook readers and publishers settle down to either support multiple formats or standardize on a single format we will see prices come into line with typical paperback book prices and probably with congruent release dates.
Just my humble opinion.
