In many cases, old songs are used precisely because they are cheaper to license.

wolco · on Jan 11, 2020

Old songs have greater surface. Many more people have heard it over something popular today which 20% might have heard of. New music is usually much cheaper. Even within the same artist. Would you lic. Bieber's Baby, baby O or something new. More extreme example would you lic gangnam style or anything newer by that artist?

walshemj · on Jan 11, 2020

Not really its why TV shows have to be careful with the budget for licences - though this can work very well "sinner Man" as used in an episode of Person of interest.