In September, just days before Borders Group met its end, one of the chain’s last retail holdouts, in the Nashville suburb of Brentwood, Tenn., was being liquidated, with prices slashed by 90 percent. It was difficult in the stark surroundings not to think of a battle waged and lost, of the armies of Kindle owners and e-book peddlars off celebrating victory while all around lay the carnage—two copies of a Paul Reiser memoir, the suspect Greg Mortensen book Stones into Schools, a still-brimming manga section. A couple of professional scavengers picked over the DVDs, cataloging them with their own scanners. Empty shelves were being stacked in the store’s growing hollows and themselves tagged with prices ranging from $25 to $50. The defeat felt so stunning because...