I think this one is pretty obvious. You can't do classical on AM, it just doesn't fit! Let's face it, back in the day classical was put on FM as part of the marketing blitz for "fine music" (and to fill the frequency when simulcasting was frowned upon), but the fact is, the nature of FM suits classical music. And all the composers being dead probably had a hand in it a$ well 8)
But as noted, LA had 2 classical FM stations for quite a while and frankly that's one more than necessary. If KUSC didn't exist or didn't do an OK job, there would be a minor outcry and someone would program classical on FM. But it does and it does, so there's no need.
Talk fits on AM just fine. If Saul comes up with some hosts that click, all will be well. For a book or two anyway, then perhaps he's go back to adult standards AGAIN. I'm about ready for All-Beatles or All-Sinatra again, aren't you?