And why not? Cumulus isn't making these changes for the benefit of any of their listeners. If I'm a listener, I know that. If I'm a listener, by definition I can already receive the 560 signal. The 810 signal might come in better, or not, depending on each listener's location. But I doubt anyone's naive enough to think this is corporate charity to make their life easier. So again, why should they care? At least until the plug's pulled on 560, and it becomes 810 or nothing.
It's not charity. KSFO is still spot sales based on whatever ratings they've got. If they don't lure the audience to where they need them before the plug is pulled on KSFO, it's a problem for them.
I told the story here (darned if I can find it) not that long ago about when KTAR in Phoenix moved its news/talk format to FM and changed the AM to sports. It was eighteen months before the audience finally fully migrated. A chunk of 'em thought they were just always tuning into a ballgame, pre-game or postgame show.
This was despite a month of heavy on-air and outside promotion about the move.
Remember: You're not the customer. You're the product. They're trying to serve you to the real customer---the advertiser.