Fiction maybe, but nonfiction, especially computer related books, second-hand is near worthless. How valuable is a book on Python 2.2 today? Cost cutting with digital versions is a very welcome change.
Almost every computer-related book I buy is theory or pragmatics related in the compilers, languages and type theory field. They're good for decades, for the most part.
Books about specific versions of software, yes. On the other hand other technical books, like CS, are a very different case and age slowly.
But following your example, Amazon sells "Learning Python" 2009 paperback for $34.64, while the Kindle /license/ version for the same edition is $25.75! And note the paperback version includes shipping costs. Paying 3/4 of the price for just a license on a single device is ridiculous, IMHO.
Sorry, but does Learning Python 2009 really have a single-device restriction?
Every single book I've purchased for my Kindle will work on my android phone, my Windows VM, and my Kindle. If I had an iPhone/iPad/iPod I could read on those as well. And they all sync, which means I am quite literally always have dozens of books with me. If I run down to the store and grab nothing more than my keys, phone, and wallet, I can catch up with my Instapaper queue while I wait on line.
If I go on a short weekend trip, I don't have to use up a fifth of my luggage on books so that I can have a book for the plane ride there and another for the ride back. If I'm stuck in an airport with nothing to read, I can jump online and download any one of over 600,000 titles (and that's just from Amazon! I also have the option of grabbing a free book from manybooks on my phone and emailing it to my kindle account.) If you want to talk about ridiculous pricing, go pay fucking $29.95 for a new hardcover in an airport and try not to appreciate having greater convenience and selection at under half the price in the space of half of a magazine in your bag.
I've been accused of being minimalist or utilitarian, and I can't wait for the day when I can afford to rebuy all of my hardcovers in an ebook format and dump the lot of them on a local library.