As much as we complain about the state subsidizing Utah athletics and the church not doing the same for BYU, it's a reality. Utah also has a track record of being willing to spend pretty big in their coaching staff - even by mid/low P5 standards (obviously not to the same extent as the biggest names, but above the median)
I think BYU would have a shot at retaining him, but it would have to come with a hefty pay raise