I think it depends on the new format, and how much it diverges from jazz. If they stay with some kind of urban music format, they'd be smart to stay with some of the same people. If they go talk or sports, they proably won't fit. The on-air people air the names and faces people associate with a station. If they want to change that image, the easiest way is to change the talent.
If they are let go, there are many other places in Philly for them to go.