I don't know where you got your numbers but they are wrong.
Again, I'm not saying you have to be top 12 in both categories to make the playoffs but the really good teams are good at both of those things (with few exceptions).
You just pointed out that 50% of the teams are in the playoffs with top 10 run games and 80% are in contention. You also pointed out 50% of teams have clinched in the top 10 at run stopping and 60% are in contention (in reality SF and Houston shouldn't count because they only have good numbers due to terrible pass defenses 24 and 32 respectively).
For comparision, top 10 passing offenses:
1. Indy - In contention
2. NO - Clinched
3. SD - Eliminated
4. Dallas - Eliminated
5 GB - In contention
6. Houston - Eliminated
7. Denver - Eliminated
8. Philly - Clinched
9. NYG - In contention
10. Wash - Eliminated
Only 20% of the top 10 has clinched and only 50% is in contention.
What would you take, 50% clinched and 80% contention or 20% clinched and 50% contention?
I got my numbers from NFL.com. I clicked on "stats" and sorted by team total rushing yards. That doesn't include the Philadelphia/Minnesota game, but that will just further my point. Minnesota is sitting 85 yards behind Atlanta for #10 in rushing offense. Neither team should fall out in rush defense.
And why shouldn't SF and Houston not count just because they can't stop the pass? SF is #2 in yards per attempt and Houston is #7. You don't get to cherry pick stats just because they don't fit your argument.
And you totally missed my point about the QBs. Like I said, they may not put up numbers but they know how to not screw up. Guys like Kyle Orton can put up numbers but no one will ever accuse him of being a good QB.
Recent stats probably will show that you don't have to be top ten in just ONE category, but rather at least in the top half of the league at both running the ball and passing the ball on offense and likewise good at stoping both on defense, good at special teams, and have a low turnover ratio.
Therefore one can surmise that you would need both a good QB AND a good running game on offense. Since we have a good running game, it just makes sense to get a QB who can actually throw the ball farther than three yards like Clausen.
But I think you hit the nail on the head here.