Brady has entered his decline phase and it's showing (hell, he's 37 years old!). His reactions are slower, his arm strength is not what it once was, and his accuracy is off because he tries to push the ball to compensate.
Now more than ever he needs to be surrounded by talent to supplement his fading skills and so that he can rely on other players to relieve the burden. And what does he have? A bottom 5 OL, zero WR's that can separate (and apparently only 1-2 that can actually catch), an injured TE with no depth behind him, and a stable of backs who get no help from the coaching staff.
There is no talent on that offense. Ridley would be talented if he could hold onto the ball. Vereen would be talented if he actually got the ball. Gronkowski is talented but can't stay on the field. Edelman isn't talented and is somehow the only weapon. It's painful to watch the Pats give this guy no help after he carried them for so long.