I think that if the Rams were guaranteed an FM signal in the market (KYSR having the right demographic "fit") they wouldn't have a problem with a co-owned AM (KFI) simulcasting the games. If iHeart can put such a deal together, maybe they could have "more stimulating" pre- and post-game fan call-in segments on KFI, with KYSR joining the simulcast just for the games.
Yeah, a few alternative music fans will gripe about losing a few hours of their music once a week, but there would be far more complaining by the listeners of the other three iHeart FMs, for the reasons Rob states.
Even though Entercom does have NFL on some of their stations, I reconsidered my original thoughts and I think they held back from bidding because with a one-station "cluster" the Rams would become an "all or nothing" situation for the listeners, who might switch over to KRTH next door or KLOS down the dial in the other direction ... and who knows when they'd remember to come back to 100.3?
One thing I don't see is Cumulus writing any kind of check to iHeart for anything, sports-related or not.