Hey David/BigA = maybe you can explain the true success of CBS-FM in the proper demos vs. what we call discuss on the 12+? It brings up some interesting conversation on here. How much longer will the current weekday line-up be around? I know (Broadway) Bill is 67-68 and has talked of retiring. Joe Causi can't be far behind. Dan Taylor has had a few issues this year, but seems to have weathered quite well. Shannon may well be there a while. I would think Dave Stewart would stick around another decade, at least.
Johnny Carson was way out of his target demo when he was still getting huge numbers. He appealed to prime TV viewers.
Same for Alex Trebek and many hosts on game and talk shows.
As long as they are relevant and have guests and topics that appeal to the advertiser friendly demos, they will stay.
You mention retiring: that is the one variable that stations can't plan too well for. If one of the big names wants to hang up his gun belt, they simply have to look for someone else who appeals to the target audience.