To increase Kindle revenue would mean jacking up the Kindle price. I'm glad his publisher isn't one of the big six dicks who jack up the Kindle price to the same as the paperback and say "it costs the same to produce an ebook". Um, no it fucking doesn't. There's no paper, no printing--all you had to do was format it for the ebook. And half the time they don't get that right. My ebook of The Hunger Games changes font size at different times. A Stephen King story collection ebook I bought has sudden paragraph breaks in mid-sentence throughout random points in the book, messed up italics that go beyond where the italics should've been, and a myriad of other problems. And it cost the same as the paperback would have. Ridiculous.
In my opinion, it's appropriate for the ebook to cost much less than the paperback.
To be fair, I have a 4-book hardcover deluxe edition of Eragon, and the two last books both have the same problem: missing words and parts of sentences. Nothing much, but here and there, suddnely the lasst 2 or 3 words of a paragraph missing. Not important if they're small stuff, but the name of who died in a big clash? Yeah, that's....annoying. It's a weird sort of error; a spell checker or such wouldn't catch it but a human editor would DEFINITELY notice it - maybe not all of the instances, but at least half - it's really quite prevalent throughout. Seems like the book was dictated with some speech-to-writing program, and the person got distracted occasionally. Psht.