Eli5 The Businessmodel of IHeart Radio. How does this work?

Occasional SYSK Listener here. I am baffled by the amount of new shows that pop up under the their Banner. Thematically these Shows are totally random and they only ever seem to get advertised for a very short period befor the next one takes their place. Are they just pumping out these shows hoping one is a hit and makes worth all the misses? How is this sustainable? Especially since they only ever seem to advertise their own networks Content?