Intereting thought you have there. People listen to their station of choice for the music, but it is the personalities that keep them coming back, and in some cases, have listeners follow jocks wherever they go.
Morning drive is set up to get people going while they are ridding themselves of eyeboogars and bad breath. Morning drive keeps them informed of the latest events that may have occured while they were sleeping, and to help make them laugh and smile so that they start their day the right way, happy.
T.V. is a painless way of passing time, and radio has this ability too. While listening to several people make fun of each other, and give their points of views on topicality, keeps one's brain moving, while starting one's day, and when they are finished with their topic, they play your favorite music, because that's why you turned on that station in the first place.