Well, I am sure it is about money and having his opinions heard. With CNN ratings at or near zero, it is pointless to be an analyst when no one is listening.
At FOX, people will actually hear him.
They use more than just 2 libs. Juan Williams, Bob Beckel, Kristen Powers, Alan Colmes just to name a few. These are the big name Dems they have on all the time. This doesn't count all of the other Dems they have on as a counter point to the GOP voices.
Every Saturday and Sunday morning, I watch MHP (Melissa Harris Perry). She never has anyone on that is conservative and or even slightly right leaning. All libs all the time. Some more extreme then others, but everyone is a lefty.