Sony wasn’t just selling a radio, it was selling a new way to consume media. Young listeners could now tune in without adult supervision (a teenage John Lennon had a transistor radio on display, the Beatles chronicler Bob Spitz has written, “like priceless art in his bedroom”). To the degree that we live in a world of pocket-size personal devices rather than one of large screens and subwoofers, we have Sony to thank. Or blame.