Looking at the contract database that was linked in the OP's link, our contract with Nike is abysmal. It's less than 50% of any other Power 5 contract reported on there, and less than 25% of the vast majority of the Power 5 contracts.
Cincinnati - an Under Armour school - gets more than 10 times what Iowa State gets from Nike. (Edit: This might not be apples to apples because there is a disclaimer on that site that some of the contracts are not annual value but overall value, but it is unclear.)
I would love to switch to Under Armour especially if it pumped $4 million more a year into the AD budget. We are getting absolutely hosed right now it would appear.