The United States is often called the country on wheels.
It is because most people in the country have a car, and after radio became a prominent part of American culture, it also gave a widespread audience to music artists, both famous and regional ones.
People were able to discover songs they never knew existed due to radio, and it helped artists get widespread acclaim. The radio even had an impact on music charts as songs that would be played on radio stations would easily become popular due to radio.
After the internet and social media boom, the impact lessened as songs started going viral due to social media. Nowadays, one could just play their Melody playlist in the car.
Radio had clearly taken a hit, but it didn't mean it had died down.
It was still a major part of the country, helping artists find more success. Even now, record labels would try to get their artists' songs on the radio.