Notre Dame was always THE PLACE that athletes wanted to play for if they wanted a combination of great academics plus playing big time football. Stanford has always had even a better academic reputation plus better weather than Notre Dame.
The edge Notre Dame had over Stanford was that Stanford sucked as a football program. However that has now changed, as Stanford has eclipsed Notre Dame as a football program. You combine this fact with their other advantages over Notre Dame, and you have the recruiting landscape that we see today. Kids are picking Stanford over Notre Dame.