Why would a rising coach go to Louisville when they're about to get hit hard? Post season ban, loss of scholarships, etc. No way.
I could have seen it as similar to when Bill O'Brien went to Penn State. Prohm has family connections (I believe his wife's family is close to that area), he has shown he can win with less talent, and L'ville could pay him a lot with the understanding that they get "best effort" results.