It's a tit for tat thing, they all help each other...if you have a strong consistent run game it makes it easier to pass, if you have the legitimate threat of the deep pass is makes it easier to establish a strong consistent run game.
But, if you are not a team who can run the ball effectively enough when they drop back to take away the deep pass (or throw the deep pass effectively enough when they stack the box to take away the run game) to actually make the defense change what they are doing, then those are the wrong ways to attack it.
Back when Rees was here, he took a lot of flack for being a terrible passer, while it is true he had a weak arm he was actually a very good passer, with great touch and accuracy. Defenses knew this and knew he had the ability to pick them apart if left unchecked, so the common theme when playing us was to drop 8 in to coverage all game long. Now if we had an effective run game that could consistently march the ball against a 3 man front, we could have forced the defense out of this and then Rees' passing would have been effective and the offense would have looked great. But our run game was so pathetic then we couldn't even run effectively vs a 3 man front, so the result was defenses stayed in 8 man coverage and since we couldn't run, Rees had to throw against 8 deep all game long which made him look like shit (as it would to almost any QB).
Now bringing it back to current, our current situation is kind of the opposite and while there are some similarities, the approach isn't identical. Here's what I mean, if the defense stacks the box to take away your run, that means your run game is what they see as your easiest path to beating them. No matter what strategy you use, your ultimate goal HAS to be to circle back to the thing they want to take away. If when they stack the line, you can throw it deep effectively (meaning actually connect with the deep pass at a very high completion rate) then that is GREAT, as long as the second they adjust to you hurting them deep you go right back to the run game to hurt them there...if you do, you get them off balance, they're on their heels and you now have the advantage....but if you don't, if you keep throwing after they've adjusted (which is what we normally do) you're gonna start having incompletions and punts or Ints...now the D won that round and you are back to square one.
Here's another part of our problem...when the D stacks the box to take away the run and you abandon the run game altogether in favor of trying to hit the deep ball every play, and you aren't connecting....now you are on a VERY slippery slope of actually allowing the defense to gain the advantage, because if you aren't connecting at a high rate and you aren't running it, now you are one dimensional and all those guys who were up there to take away the run, now they have their ears pinned back on every other play and the plays in between are lined up like they're rushing but really bailing into coverage. This is the worst nightmare for ant QB....he knows every play he's throwing against vs one of two scenarios 1) under duress because they bring more than you can block, or 2) into 7 or 8 man coverage and you don't know where defenders are because they are dropping to coverage from unorthodox places on the field.
The solution to both of these (Rees example and our current struggles) is really quite simple if your team is good enough to perform it and your coach is collective enough to follow the plan in entirety to full fruition (getting back to doing what they were trying to take away) instead of being glamoured by a little temporary success and jumping off the tracks. Because then the plan typically backfires and you think 'oh that plan was bad' but the truth is you screwed the plan by going away from it.
So the plan for both those situations is identical, but opposite. With the Rees one, you attempt to run the ball as long as it's effective enough to keep gaining first downs against the 3 man front, while sprinkling an occasional pass in there just for show. After you've picked up some first downs they will eventually adjust (but they'll try to mask it, with some line up 8 deep looks with predesignated run blitz) as soon as they do you hit them with the pass. Now, you don't have many chances at relying on the run vs the 3 man front...if you try it a few times and you can't get positive enough yardage to consistently be in 3rd and 3 type situations, you gotta go plan B. Plan B is using all the short, quick hitter, draws, delays, screens, slants that PB was talking about [Spoiler Alert] Plan B here is the same as Plan B in our current situation. You use all the things PB talked about to pick them apart little by little, then when they adjust to that (come out of 8 deep) you go right back where you wanted to be with Rees picking them apart with accurate mid range passes.
So now for us in our current team situation it's the opposite, they have line stacked to prevent the run, so you attempt to throw the deep ball as long as it's effective enough to keep you out of 3rd and 10 (or longer) situations, while sprinkling an occasional true run play in there just for show. After you've hurt them by connecting at a high rate with some deep passes, they will have to adjust (but again they'll try to mask it, with some line up 8 in the box looks with predetermined all out bail out into coverage) as soon as they do you slash them with the run. Now, you don't have many chances at relying on the deep ball against the 7 or 8 man front, if you aren't connecting...if you try it a few times and end up in 2 or 3 3rd and 10 situations or it leads to consecutive 3 &Outs, you gotta go plan B. ***Plan B was already outlined above*** You use all the things PB talked about to pick them apart little by little, then when they adjust to that (come out of 8 man fronts and all out pass blitz) you go right back where you wanted to be in the first place with Dex and Jafaar slashing them to the body and Book killing them with play action passes run off successful chunk runs.
Kelly is GREAT at so many things outside of game days...he could literally run circles around me (and probably anyone on here) in about 95% of what he does. He problem is he gets one tracked or off tracked so many times in game situations. He either just keeps throwing deep even if it's not being successful (while forgetting to sprinkle the run in) or once he gets the D on their heels with the pass and they adjust, he's so BIG eyed at the passing success that he forgets all about bringing it around full circle and going back to the run....that is typically right when you see these electric looking drives where we look unstoppable and can just mail up our final score, fizzle and turn into 3 straight incompletions and a punt or FG attempt, or an interception.
This same trait (flaw) has been visible in him every year he's been here (and that's coming from the biggest Kelly fan boy there was, when he was hired) which I why I think he will never change and every year we keep him here will just be another wasted season. Let's say we make the playoff this year, and represent well but go down in defeat, then a near playoff miss followed by a couple obligatory mediocre Kelly years....when this guy is approaching 15 years on the job with zero NCs, are you really going to feel that those 15 years weren't wasted?
Anyway, I digress...the point is what PB was saying about mixing it up is spot on, what you were saying about the deep ball opening that up, while not specifically wrong, is only accurate IF you are actually hitting those deep balls at a high rate (while not forgetting to sprinkle some runs in and then going to the run game altogether as the defense adjusts to respond to being hurt deep