I think you hit it. I was at the opening game of the Big 12 between KSU and ISU in Ames and commented afterward that they were the to worse teams in the Big 12. I think the ISU WVU game in Ames might have bought Prohm another year to prove he can get and keep ISU in the upper half.
His theft of Illinois' '18 high school talent is what has garnered him more time, imo.