I think publishing is much more complicated now than it once was because books can come in so many different formats. You'd think big publishers would be embracing the idea of eReaders and trying to get their books out to a wider audience. But it seems they're not, a lot of the ebooks from traditional publishers are priced way too high to compete with some self-published authors. And this is all because those big publishers want to protect their book sales.
I'm not going to go into this matter in details because Joe Konrath and Barry Eisler do it brilliantly in this blog post: