Give me the text and I'll add a version of Readability (same typesetting for all fiction books would be fine for me, there might be particular text features that need specially treatment occasionally I imagine). Cover art is usually pretty formulaic I can't really see most authors paying [to a graphic artist/designer] more than a days wages for subsequent covers, perhaps a week for the first one.
Presumably with an e-book reader I can set set the kerning/leading/font-size/font-weight/etc. ?
With e-books you could set 2 prices, edited and unedited, call them different names if you like. Then authors can decide how much they want to spend on editors - in some cases I'm sure they add a huge amount, probably define the work, in others not so much.
I guess director's cuts of DVDs create more overall profit? Why not the same for a book?
However, my main thought was that if the original sells better one could consider ditching a costly full-edit and simply having it sub-edited or even skip to proofreading only.
I've seen every error you can imagine, from the wrong table graphic being used to pathetic OCR errors or just plain typos. And the cover art, at least on most of the ebooks I've purchased, is nonexistent or extremely unimpressive. As a consumer, I certainly don't feel like ebooks are worth the prices being charged.
I am less certain than you / the publishers are that the market really gives a damn about all that. For most readers, a plain epub may be good enough.
Is that expensive effort necessary? Or does it have the nature of gilt hand-illustrated drop caps: something that the market learns to live without in return for a radical reduction in price.