Another things in common in all of the Packers losses.
The offense struggled...
As shocking as it is... every Packers loss isn't completely and totally on the Packers defense.
Against the 49ers the Packers offense struggled. The RBs weren't able to pick up 50 yards on the ground. The OL struggled protecting those behind them and Rodgers made less than 57% of his passes.
Against the Bengals, the Packers defense might of been the best Packers unit getting 4 turnovers and other than giving up two long drives did a great job where as Special Teams and Offense struggled turning over the ball a lot and basically put the Bengals in position to easily score more points than the defense did.
Against the Bears, the OL couldn't protect Rodgers, he got injured and the vet back-up looked very rusty and struggled a lot espically with throwing anywhere near the very tall DE Peppers.
Against the Eagles the offense couldn't finish until it was too late.