The hardback version has extra value: offline ability, future-proofed technology, DRM free, prestige value on the bookshelf, and easy resale. However you are right in that the price is bottom-bounded by the factors you mention, time and ability.
Why has the softback version of a book always been considerably cheaper than the hardback? It's not harder to produce, and the difference in cost in materials is insignificant. It is because by delaying the publication of the soft-back they know they can price gouge real fans who must have the book "now".
Not passing on cost-savings of the electronic version over printed is as wrong as assuming no distribution cost means something is worth less in terms of content. Some books are better than others, some longer, some must-have tomes to be re-read over and over again, some to be read in an afternoon and forgotten. Price is an arbitary thing to set, and it's not on what it is worth but what will generate the most revenue.
Amazon is there to optimise revenue, which in theory should work out in favour of the author and publisher. Why don't bricks and mortar adapt to the ebook? A bit like cinema adapted to the dvd. Here is my vision:
* large coffee shop style lounge areas to read, as you have already
* pick up an ebook on your way in, log in using your shop membership username and password (or come in with your own)
* the walls are covered in massive colour touch screens 1m x 1m, tiled with book covers with synopsis underneath
* you can swipe the screens to scroll through books, hit buttons to drill down by category/author/etc
* pressing one of the covers zaps the covers, index and 1st chapter to the ebook you are reading
* at the end of the chapter there is a "Buy now" button, which when you hit it has the same monetary distribution (ie 1/3 to the store / publisher / author)
It would provide a venue to host live Q&A with authors, a more social place to browse where you can look over other people's shoulders, an interesting refuge whilst the SO is clothes shopping.
Phillip.