I think McDaniels is smart. He realizes that most people get one, maybe two shots to coach in the NFL. He's biding his time knowing that he's still going to have a great offense at his disposal next year so his stock is very unlikely to fall. He can wait for the right opportunity. You'd think that the Falcons would be that opportunity, given their talent, a solid QB and Dimitroff/Pioli there as well.
Maybe McDaniels is leery of Pioli's ability as a talent evaluator. Maybe he feels that the shake up means another bad season and the pressure is on.
Meanwhile if he stays here he further ingratiates himself to the Krafts and as long as they keep making it to AFCCGs and SBs he'll always be a guy people are interested in.