I've come to the conclusion that Nick Saban hires all these former head coaches for just one reason: to fill out his coaching tree. He wants his tree to be bigger, far, far bigger, than any other coach ever. He's building legacy.
He's already got the GOAT on championships. He's building to GOATness on myth (though guys like Rockne and Pop Warner and Walter Camp and Vince Lombardi have some pretty hefty myths and legends). With this one little trick, he can become GOAT as a coach's coach, too.
Cynical, yes. But can you think of one other sensible reason he would hire Butch Jones or Derek Dooley after they were so badly exposed? Heh.
Go Vols!