I really have to wonder - what % of KNBR listeners use the FM over the flamethrower AM? Why doesn’t Cumulus take advantage of the fact that KNBR has a solid AM legacy signal? I still hear people telling me to listen to the game and giving me their AM signal far more then the FM signal.
Cumulus could try any other format on 104.5, surely it would be better for their billing as a whole.
Single-line reporting makes it impossible for us to know for sure, but what I have heard from PDs of legacy AMs that begin an FM simulcast (and I was ND at one of those until four years ago) is that unless your FM signal is substandard, within a year at least half of your audience is listening to the FM instead of the AM.
If KNBR were to flip 104.5 to something else, a significant number of those listeners would not find their way back to AM, and would likely start listening to The Game instead.