You can say a lot about BYU's recruiting limitations. But one thing we haven't struggled with is finding really good QBs. And when you have a really good QB, you are going to compete in and win a lot of games you otherwise wouldn't. Northwestern doesn't have near the QB tradition that BYU has, and frankly not many schools in the country do. Jaren Hall, for as little pub as he gets nationally, was easily a Top 20 QB in CFB last season, and he isn't even one of our more decorated signal callers. So long as BYU consistently gets high level QB play, we'll continue to outperform our recruiting rankings.
There's one common denominator in all those wins over Nebraska, Michigan State, Tennessee, Mississippi State, Texas, Oklahoma, Miami, USC, Penn State, Notre Dame, etc. Despite the fact that those programs were generally far more talented than BYU, we often ran onto those fields with the better QB and that can make up for a lot of other deficiencies.