Have most played ball at some level?
Graduate assistant
Special teams coach?
QB/RB/WR coach
Offensive coordinator?
Head coach?
I know on occasion HS coaches have been tried, with sparing success (I think).
If they spend say 2 years, 4 years, 4 years, 6 years, at those slots, they spend a lot of time before being potentially HC, at the early age of about 38, at best. How old is Scott Frost? And they could have periods of unemployment in there somewhere.