As an ND fan, you usually do not see ND head coaches go on to be a head coach elsewhere or even coach as an assistant. The only two I can think of are Charlie Weiss (Kansas) and Bob Davie (New Mexico), and that took quite a few years in the broadcast booth before his tenure as HFB coach at New Mexico. I could be wrong. Maybe there is more former ND HFB coaches that I have missed. Maybe @Bobrefwould know better.
I always wondered about this.