It's not unreasonable and not a stretch at all to say that opposing coaches looked at this offense with Romo out, Dez out and no Murray, and said, "Know what, we can afford to be ultra conservative on offense and eliminate mistakes, not give them any turnovers then when we need something, we go get it."
The 2 or 3 really good offenses we faced, blew us out. The rest of them rather they be bad, mediocre or fair to middling, somehow managed to get what they needed when they needed it just about every time, even driving the length of the field on us when needed.
That means your defense sucks. Let's not delude ourselves.