Along with any hopes he can pick up where he left off on his radio show/FNC gig. He has probably lost 2/3 of his previous audience anyways, and he wasn't one of the highly rated talk show hosts to begin with.
He may have started losing listeners/viewers/fans when he was one of the very few national "conservative" radio talk show host to come out and back amnesty. Maybe that was the catylist for him to get his White House job. He figured his talk radio career was about kaput, anyways, so he jumped at the chance to get the job he always dreamed of having.
Medved and Hewitt are the only other national "conservative" radio talk show hosts that I am aware of to come out and back amnesty. They have probably lost a good chunk of listeners as well.
I imagine the ratings at FOX are going down significantly, too, as they shill for the admin on the subject -- I won't listen.