You take my example much to literal. Not ONLY one song. People keep their favorite Song(S) ready to go on their own personal device.
Personal music devices are more of an issue to the record labels than radio. People have had personal music devices for over 40 years. It doesn't scare me one bit.
Radio IS adapting, but many boomers are having trouble accepting the changes. They feel radio has to do what it did 50 years ago to compete. That's not true. As I said, currently people use a number of different devices for music. Radio is one of them.