So what you are saying is that there is no correlation between being a coordinator and a successful head coach.
Because head coaches like these were coordinators:
Nick Saban
Kirby Smart
Dabo Swinney
Gus Mahlzan
Lincoln Riley
Brian Kelly
Dana Holgerson
Chris Peterson
James Franklin
Josh Heupel
Mark Stoops
David Shaw
Mark Richt
Paul Chryst
Mario Cristobal
Tom Herman
Mark Dantonio
Mike MacIntyre
Dan Mullen
Dave Doeren
Justin Fuente
Mike Gundy
Bryan Harsin
Kind of annoying, but I just went through the current top 25 AP and coaches. 88% of these head coaches were coordinators (OC or DC).