This is probably the argument I would try to make.

There is no correlation between prior FBS head coaching success and future success in the modern game. However, you could argue that you need said success at Notre Dame specifically. Even there, though, I would say that's a case of correlation not equaling causation. Can anyone point to why you need that experience specifically at Notre Dame to win big versus, say, USC, Georgia, Clemson, etc?

If Kirby Smart came here instead of Georgia, does anyone doubt he'd be doing an outstanding job in South Bend?

The fact of the matter is that unless you're hiring someone like Saban or Meyer(not at all realistic at this point) anyone you hire is a gamble. Including those with decades of experience at the FBS head coaching level.