In a nutshell, it's good to now allow many sacks, but the stats show it's more about your QB than it is about your OL. So that's not a valid support for the claim.
As an aside, I was doing a though experiment as I walked my class to lunch. People don't like the WAR stat in baseball, but it at least does a decent job of taking everything into account and producing one number. Yes, it's an equation, but it got me thinking about different little truths in football.
Like....a yard of rushing is worth more than a yard of passing. One could think a yard = a yard, but there's two reasons for this distinction:
1 - a yard of rushing takes more time off the clock. So you've gained that plus outcome and gotten closer to the end of the game, so it's slightly more valuable., and
2 - teams always average more yards per pass attempt than per rush attempt, making passing yards more common per chance, so each yard of rushing is worth slightly more.
If you can handle that, we can move on to the next idea:
A yard prevented is worth more than a yard allowed.
Again, two reasons for this - one anecdotal (but I believe supported by evidence) and one theoretical-valid):
1 - teams with great defenses tend to beat teams with great offenses, at least in big games. We mostly feel this to be true and there are many instances, but if we really researched it, I think we'd find it's the case, and
2 - the fact that if you don't give up any points, you can't lose the game. Your offense can gain nothing and you score no points, and you'll usually lose, but sometimes you'll garner a tie. But when you allow no yards and no points, you can't ever lose, the worst you can do is tie. This is just a logical outcome to a radical "what if" scenario.
So where to go after these, I'm not sure. Yes, you could break it down to this:
a rushing yard prevented > a passing yard prevented > a rushing yard gained > a passing yard gained
If anyone wants to dispute this or talk about it, let's do that before moving on.