Sonia Land tells it like it is. Publishers cannot hope to avoid 50% net for ebooks in the medium term, at the very least on back-list titles:

Publishers can so simply redress this threat: their main concern therefore must be to secure book rights and this they can easily do by offering a fair rate to authors for their e-book rights. If any publisher offers an author 50% of net proceeds from the sale of an e-book, an agent will be hard pushed not to go with them even if the author can get 70% from the online retailers.  And I will be happy to go with a publisher because I believe they can still publish a book better than anyone else.

But does this mean that a publisher will lose out financially? I really don’t understand why the financial guys in the publishing world don’t do their sums properly. No matter how a publisher tries to gloss over the figures, there are huge profit margins in the sale of each e-book. There are no paper, print, production costs; no distribution costs in a time of ever increasing fuel prices; no need for inventory control and yes, let us not forget the bane of all publishing companies – return of books! And one last big plus: every sale is a cash sale!

via Publishers should improve their royalty rates | FutureBook.