What does a great running offense average per run attempt? 4.5 to 5 yards?
I think in good weather, with Brady, his average per pass attempt is so much higher than that that the chances of keeping a drive going with at least 2 passes per series is significantly higher than with more than 1 run per series.
Passing brings lots of other things into the game -- sacks, more holding, interceptions. But running is not without risks too. Fumbles, and, like we just saw, holding.
It also doesn't allow for ball control, clock running types of offense. But the way our hurry up is designed, we aren't trying for that kind of offense.