I wouldn't count on them ever touching Gio. Agreed on Tony and Davey though. PRO-FM like HJY would have to make some serious blunders to alienate their audiences. In PRO-FM's case, a serious blunder would be breaking up Gio and Kim or changing the music drastically. Bristol is a good programmer but that doesn't matter in this day and age and it won't matter to Cumulus as life will go on without him. Davey is a throwaway and has been for years.
As far as the whole social networking thing I agree it's important but how important is it when you compare it to the theories about talking to listeners on the phone or playing requests back in the day? I don't care how many people befriend you. Only a very small percentage will ever interact with you. They'll get updates on the station and the shows as Facebook friends but a lot of people just gloss over that stuff and interact with who they want to. Unless you know the radio personalities personally, only a fool would think they're really interacting with you personally. It's just another method of promotion and a good one but not something you can someone from a morning show for just because you can replace him with a younger and probably more socially interactive guy with less life experience.