Yes, hard work can get you a good education at any school (or even without a school, I might argue). But some institutions do provide a better range of experts in their fields, and rankings sort of loosely reflect that, and that can in fact produce better opportunities to learn more and gain greater expertise to ambitious and hard-working students at such institutions. And Notre Dame is among the Top 20 or so, roughly, I think, considered in this way. As the ratings usually reflect. So of course the motivation of the student him/herself is the biggest single factor, but some schools do in fact offer a better chance to learn a lot in your field than do others.