Michigan brought in a high priced guy. What do they have to show for it. Texas has struggled for years. USC? Ol' Miss? Kansas has been paying for 3 coaches at the same time. I think Wiess is still on their payroll. MSU, Illinois, Kansas State.... Like I said, only 15% are 'earning their money' — based on your logic.
Rich Rodriguez was awesome at WVU. Then he took the MI job. Suddenly, crap. Then the AZ job... meh, then crap. So, much of finding the right fit is luck. Someone can rock it at school A, but suck at school B (Taggart, Chip Kelly)....
BYU, by contrast, hasn't really blown too many hires – especially position coaches. LaVell was great (as were the vast majority of his assistants and cooridinators). Crowton looked like a great hire, but fizzled out (note: after BYU he coached/OCed with Oregon, LSU, Maryland and others). Bronco turned out well. Kalani and his whole staff were first timers... and have improved with time.... so, your argument isn't really on target.