Clearly a large majority of you overlooked a point the OP made:
"Teams are averaging a middle of the NFL 32.8 passing attempts a game, so it can't be argued that teams just decide to run the ball all the time, because clearly that isn't the case."
So it is not that opposing QBs aren't trying to pass much. And most of the time, quick and large chunks of yards are obtained through the air. If our pass D was not strong, we would have seen a lot more points racked up against us. Let us give credit where credit is due - our pass D is good.