On the macro level, the SEC has never prohibited gray-shirting, like some other conferences did a long time ago. Saban uses that.
On the micro level, he uses one-year, rolling scholarship contracts. Academic requirements are far looser, and discipline far lighter. JUCO's are always in play.
I agree that Saban would feel challenged to excel at the same consistent level at Notre Dame. No grayshirts, four-year commitments to the athletes, high academic requirements, rare JUCO use, and (as we know), severe penalties for academic and legal problems. We all know that Lou was challenged (and upset) by ND's admission standards.
It's harder here, for sure. Not to deny Saban's genius, but the off-the-field advantages he has in Alabama sure help.