Simple answer: you don't have to worry about royalty fees for talk radio shows.If that is true, why is the news/talk format still common when their demos skew 50 plus and older? Are there reasons why old talk is more desirable to sell than old music?
Complex answer includes 1.) the inexpensive nature of syndicated talk radio shows as opposed to staffing for a music format, 2.) talk radio having a different ecosystem for advertising (expounded on in the "Is WABC Number One?" thread) and 3.) talk stations like WHK broker out their entire weekend to outside producers—WTAM is almost an anomaly in that they don't have much brokered programming.