This is another one of those things that is great in theory but execution is another story. It's so tough to be willing to give up yards but then turn into a elite defense when the offense gets close to scoring range. It's a fine line that is really easy to cross.
What I don't understand is, why not attempt to prevent yards as well as scoring.
Because yards don't really matter, at the end of the day if you keep points off the board it was successful, regardless of how it happened. The problem lies in the fact that you basing the success of your defense on a few key things like turnovers, and you HAVE to stop them on 3rd down otherwise you just keep bending and eventually break. I don't have any doubt that this can be successful, but I do doubt if it can be successful and consistent. I think trying to dominate everything aggressively on defense is a more consistent approach to success. Defenses like bama or tcu or msu (all who run very different schemes) are good because they try to dominate every down, they have a aggressive mindset and attitude. My hope is that this year, because of the talent improvement, they become more proactive in trying to force turnovers and stops. It's still going to be a soft bend but don't break defense but hopefully they do something to bridge the gap between ultra conservative and really aggressive.
I will never understand the argument that yards do not matter. If your opponent has put 400+ yards on you that means they have held possession of the ball for a great deal of the game. In addition, it leads to your Defense getting tired because it can not get off the field and your Offense isn't going to be clicking because it never has the ball. Add a turnover or two on Offense and you are bleeped. You do not have to take my word for it, just watch film for the last several years and see for yourself if yards do not matter.
You're equating yards with ToP, which are not really connected. Here is the top 15 in total offense followed by there ToP ranking
1. Baylor - 112
2. Oregon - 122
3. Fresno St - 100
4. Texas A&M - 115
5. Northern Ill - 95
6. FSU - 71
7. Ohio st - 33
8. Texas Tech -98
9. Indiana - 120
10. Clemson - 110
11. Auburn - 49
12. Marshall -114
13. Washington - 93
14. BYU - 105
15. San Jose st - 43
At the end of the day its about points, everything else is secondary. Would you care how many yards we gave up if the defense could consistently get stops on 3rd down? Part of the formula has been working, Teams generally need multiple play drives to get down the field and score on us, on those drives are multiple 3rd downs that the defense just folds (88th last year for 3rd down defense). We get a stop on any one of those and the drive is over, points are avoided. Like I said I dont really agree with the approach of sitting back that much, but if plays are made on those key moments it can work.