Where did he go wrong? He wasn't a good coach. He never was.
He didn't go through the Darwinian process of working his way up through the ranks, proving himself, and earning his promotions like most coaches. Jerry was seduced by the glory days connection, the Troy and Moose endorsements, Daddy Garrett being a Jerry loyalist, the Ivy League degree, and the rest of the garbage that had nothing to do with being a good coach.
Still can't believe we wasted 13 years on him as OC and HC, but then Jerry is that big a selfish, nepotistic football moron.