Extremely typical. There are cases where the highest paid employee in an entire _state_ is an athletics coach at a state university.
Professors can't do what he does: bring in big-ticket spending, sponsorships and donations.
Basically, people don't act rationally so the market is irrational.
I wouldn't so quickly ignore the additional tuition revenue athletics departments bring in at non-Tier 1 schools.
University athletics are a weird thing. But if the pay bothers you, think of it as a commission. Going cheap on that will likely cost more than it saves.