Colin Cowherd had an interesting take of coach salaries. His view is the current coach salary even if higher doing more for the program than the last, and by how much. Saban for Example is bringing in hundreds of millions for Bama, and Shula did not get in that ball park. The Michigan coach the same. Hud really has overdone Bustle by a mile, even though he might be a ribbit, and not a turtle.
A word of caution, never pay a guy more than you can afford to buy out at any point.