University Business did a ranking a few years back of the US colleges with the most ultra-wealthy alums (>$30 million net worth), ND came in at 16th with just over 2,800. Now granted, most of the 15 ranked ahead of ND are not FBS programs. The only other FBS programs ahead of ND are Stanford, Northwestern, Texas, UCLA, USC and Michigan. And half of those schools don't have the football prestige that ND possesses. So it's basically USC, Michigan and Texas, and the gap isn't really that large. I think USC was sitting at just under 3,600.
So ND can absolutely throw them dolla bills all over and they're far more willing to spend and invest in football than they have at any point in the past 30 years.