I think about that a lot actually and I think where I am at is this: we know at the individual game level it's always execution, we also know that the trend is present across many years and different players..so how do we reconcile those two things?
My thesis would be that it's a structural issue. It has to be or it wouldn't repeat itself like it has. So what's the issue?
I am asking here because I don't know but it makes sense that a pass first offense that wins by having an NFL system and NFL WR talent gets compressed as the field shrinks. The back of the end zone becomes the extra safety that prevents you from taking the top off the offense? I mean that's football 101 so maybe too simplistic, then again maybe it's just that damn simple.
X & O gurus would have to chime in on Day's passing offense being more vertical than say a Shanahan offense that seems to always get guys open in any part of the field? Anyway, my .02. I feel like it is some kind of structural (scheme structure/not personnel) issue or it wouldn't be as persistent as it's shown itself to be.
To answer the "just fix it if they see it" question- that's the whole point of using the word "structural" it may just be a feature, not a bug so to speak. The trade off you have to live with if you are going to have the other features.