There was a time with broadcast television's economic model when it made a lot of sense to spend a lot of money on celebrity journalists. But now, we're in an era of media fragmentation, which is only going to get more extreme.
Why would (CBS) spend all that money hiring her away if they weren't hiring her because she's a superstar.
She might alienate as many viewers as she attracts. It's an awful lot of money you're spending on her, so just to break even you've got to increase your audience by a significant amount.