Could be both: advertisers insist on running the ad a certain number of times AND there are fewer advertisers than before.
They do believe in saturation and yes there are some people
who tune in and out of games but many of us, of course,
listen to much if not all of the game and it can get annoying!
Another overplayed ad, lately, is the Foxwoods one for the
Gloria Estefan concert.
BTW, why would Howie want a radio ad about possibly wanting to live near to where Howie lives in Wellesley? There are also people who listen to his show who hate Howie, and Howie wouldn’t seriously want any of them to become new neighbors of the entire Carr family.