Imo AD's want someone they feel is more experienced and " well Rounded ", like themselves. This may be more towards an ego thing; with exceptions like Urban. You also may have a lot of political factions an AD doesn't want to deal with; especially with former players and coaches.
I am sure Coach Frost would have taken our position if offered; I believe he would have far out performed Coach Bo in the long term, in regards to attaining the top level. He would have hired good assistants; and maybe avoided the carnage of the last three coaches hiring the wrong buddies ( tired of being worst in the nation at various things and performances ).
Not all young coaches think a Youngstown type job can be a show starter. Better to get your credentials and recruiting areas at a name program.