Don’t mock the beleaguered Nook owner. That could have been you. Five years ago, when the nation’s largest chain of bookstores released an e-reader that it promised would best Amazon’s Kindle, could you blame the poor souls who bought in to Barnes & Noble’s vision of the future? In 2011, Consumer Reports proclaimed the Nook the best e-reader in the land, saying it surpassed the Kindle in just about every way. Well, that sounds pretty definitive, doesn’t it? No wonder your aunt bought you one for Christmas. Things haven’t played out well since. After failing to douse Amazon’s Kindle, Barnes...