So far this half we have seen:
1) Brady make bad throws (that last throw on 3rd down was a dead duck. Simms is FOS when he said it was tipped)
2) Receivers drop passes
3) Receivers run short routes instead of pushing deeper towards 1st down market
4) Too much passing on 1st down instead of establishing more of a run tempo. This is very important given how much stress it outs on a defense that is getting worn down as the season progresses.
5) Not enough push by the interior D-line.
Steelers are very beatable but we are seeing mental mistakes by Brady and a poor game plan by the offense.
You have a great point about wearing down the defense. The Patriots defense, at least up front, are all veterans. A running game the last few games of the season, even if it meant a loss or two, would give them a bit of a blow prior to the wars beginning...as long as they could piece together some decent drives with the running game.