If White and Caldwell return, that means that the firing of Mayhew and Lewan was nothing more than a front-office power move for control of the team. They answered to Bill Ford Jr. and had to go. That means none of this was actually about football on the field, and all about family politics.
Indy let go of Caldwell because he couldn't make 2nd half adjustments. He's demonstrated the same problem here. The Fords have already announced that White will be retained in some capacity. What GM worth his salt would be interested in taking a job with those two guys hanging around ? The Lions could have easily fired Caldwell, hired Austin as temp coach, and made Cooter the offensive coordinator to get through the season. That didn't happen because Caldwell's job was never in danger at any point, and he knew it. It's not now, and there ain't a GM out there that's going to take the job under those circumstances except Sheldon White.