The Bears flew McCarthy in on a private jet. The bears normally fly HC candidates in coach (no pun intended). So, they clearly had serious interest in McCarthy and McCarthy in them.
And, McCarthy is in a position where he can pick and choose who he wants to talk to. He's not a young coach who has to do the entire interview circuit.
And it's possible that other teams already know that McCarthy wants to come here and that we are going to hire him as soon as we comply with the Rooney rule.
Also, I don't think anyone other than the Raiders bothered to talked to Carroll. And, IIRC, Vrabel didn't talk to anyone other than New England and it's not like he wasn't a sought after coach.