If he takes a "big time" job he has three years to win or he gets fired. At anytime during his tenure if he loses for three years he gets fired.
Then where does he go? USU, Hawaii, Nevada? He doesn't want any of that.
At BYU he can stay forever. He's already earned that. He would have to lose 5+ years in a row to lose this job. Better job security at BYU.
Same reason Whitt never left for a bigger job.
He's already earning in the $3M range and the new contract that will come with the B12 will pay him the average of the B12 coaches.