to get a program to the top of its conference and national rankings?
TCU is 12-0 in Sonny Dykes' 1st season as HC. USC is 11-1 in Lincoln Riley's 1st season as HC. Each may be in the 4 team playoff. So it does not require 5 - or even 2 - years. It can be done in 1. Of course, neither Dykes nor Riley is over 70, and neither is known for being expert only in recruiting.
TCU is 12-0 in Sonny Dykes' 1st season as HC. USC is 11-1 in Lincoln Riley's 1st season as HC. Each may be in the 4 team playoff. So it does not require 5 - or even 2 - years. It can be done in 1. Of course, neither Dykes nor Riley is over 70, and neither is known for being expert only in recruiting.