One advantage of Kindle is that it provides a new tool for mental accounting. Call me irrational but formerly I could not read more than seven or eight books at a time without abandoning some of them midway. Kindle (like Netflix, I might add) gives me a new queue and allows me to have more "hanging," partially unread books at any point in time, yet without disrupting my mental equilibrium.
I have just one book on my Kindle so far, so I have not yet been able to gauge whether Cowen's assessment fits my experience. But it sounds like a reasonable hypothesis, especially considering I have to hurdle a metropolis of partially-read books on the scale of the trash-built apocolypse in Wall-E just to climb into bed.