It's the same theory as Rod Marinelli,Jeff Heath, etc.
Just because the new guy sucks doesn't mean the previous guy was suddenly good.
Darian Thompson sucks at safety? Jeff Heath is the 4th safety in Las Vegas. He sucks too.
Mike McCarthy is basically Jason Garrett who once got to coach Aaron Rodgers. Garrett is awful as an OC in New York. Great person, horrible football coach.
Mike Nolan could not get a DC job in the NFL for the past 6 years until McCarthy came along. Meanwhile, Rod Marinelli is now just a position coach in the league. Both are outdated and ill-equipped to be DC's at the NFL level.
Look at the former anointed Cowboys coaches:
Kris Richard was once being looked at as a future HC. Now? out of the league.
Sanjay Lal was allegedly an innovative WR coach? He's now just an offensive assistant for the Seahawks.
Scott Linehan? Currently the assistant OC for a very bad LSU offense.
Special Teams Coordinator Keith O'Quinn had zero business in that role. He's been put back in an administrative role with the Front Office.
Matt Eberflus might be one of the very few anointed Cowboys coaches from the past decade that has found success.
Kellen Moore and Will McClay fall in the anointed category for me too. I don't think they are what many here keep claiming they are. I also think this will be proven true in the very near future.
Bill Callahan and Frank Pollack spoke out against the suspect culture on this team. They are both still decent coaches.