Sometimes coaches lose it when they get older. It happens to everyone. Although, I would bet against with Marinelli. He has been one of the very good NFL defensive coordinators for a long time. Fact is, Wade Phillips, Marinelli and to some Zimmer have all been here and their defenses have all struggled. Phillips and Marinelli are two of probably the top 10 defensive coordinators over the past 20 years.
Maybe, just maybe, part of the blame should rely on our talent collectors. I know a lot seem to think they walk on water and I think in some cases they have been better from the terrible years where they were just awful. But how about finding scheme fits for these coordinators and not 2-3 excellent talents and then surround them with slop? In addition, that doesn't mean you take recommendations from Marinelli on who to draft (when he told them a D tackle didn't fit his scheme after months of scouting these players). Sure, you want his opinion, but your job as a GM is find the right fits so he can run his defense. It seems like every year we are always a few players away while some of our players do not feel like scheme fits in the Coordinators defense. It is a brutal cycle.