I’ve been fascinated by single-purpose devices such as iPods for music, flip-phones for communication, and e-readers for ebooks. Considering that my interest for these devices has reached an all-time high, I was wondering: Why has the iPod died out while e-readers continue to thrive and see growth? Don’t they both serve the same purpose of allowing users to enjoy one (primary) form of entertainment? Aren’t both types of devices easily replaceable by a modern smartphone or tablet today?