One correlation that I have not seen mentioned is blood trailing. I agree that, anatomically, there is no dead zone. I think we can ALL agree that a double-lung hit puts an animal down quickly (if we didn't, ethically, we shouldn't be bowhunters).
Deer that are hit high, especially if there is no pass-through (the scapula can be a factor here), have bleeding that is primarily captured internally decreasing blood loss on the ground and complicating blood trailing.
I shot an anterless from the ground this year. The shot was high through the lungs. In the 30 yds he covered before resting for good, there wasn't more than a spec of blood on the ground; but, when I field-dressed him, all that coagulated blood came spilling out of his chest cavity. We've all experienced this before.
My point: is a dead-zone more of an excuse for not recovering deer that were "hit high", because our ability to track these deer was compromised by a lack of blood on the ground?