Cotton Bowl = 92,100, TX = 100,119, OU = 82,112
I agree it is much more neutral for both teams based on location. But saying it is bigger venue for both is not correct.
192 miles OU to Cotton Bowl
197 miles TX to Cotton Bowl
The even ticket split, equal distance and the fact the game happens at the Cotton Bowl which is on the Texas State Fairgrounds during the Texas State Fair is a major contributor to them always holding the game there...