Although only a few companies dominate the e-bookselling landscape, publishers are nevertheless able to hold the line on pricing and discounting to what they feel is a sustainable level.
However, because there are only a few players in the e-bookselling world, it becomes very tempting for authors to deal with Amazon, Apple, B&N, etc. directly in order to maximize their revenue. Publishers lose some of their top authors because of these direct deals and instead have to re-imagine themselves as packagers offering a collection of services.
Authors then have the choice of whether to handle their editing, design and marketing themselves and have their agents negotiate deals directly or take a smaller cut in exchange for publishers handling these nuts and bolts items for them. Some publishers probably survive, but they’re not as crucial as they used to be. Authors have choices, though they are likely going to have to assume a great deal of responsibility for marketing their own work.