It might be....but so's almost everything else. I watch teams consistently make holes. I watched teams that have O-linemen engaged with their man but the line is getting pushed forward (which allows the RB to get some momentum, even if it's not a huge hole). I see correct double teams and 2nd level blocking. I watch coaches or QB audible surprise defenses. I watch QB's either design run or option run for good yards and 1st downs, which definitely effects the defense, makes them more cautious.
We either have none of that or way too inconsistent.