In the 1920s, radio was to music what the Internet is today. When commercial radio was born towards the end of the First World War, no one played records on the radio. In fact, for much of the 1920s, it was illegal to do so in many countries. Why? Because the music industry was scared. They thought if people could get their music free over this newfangled radio contraption, they wouldn’t go out and buy records anymore.
At the same time, musicians’ unions were afraid their members would lose work if radio stations just played recorded music as part of their programming. That’s why in the early years of radio, stations were required to have so many hours of live music every day. No one stopped to think that radio might actually increase record sales and thereby make money for musicians.
It seems silly now, but that’s the way it was in the 20s.