I think only looking at TV money is incomplete.
Iowa State fans would pour money into the western Big Ten schools -- we are a small but dedicated fanbase that likes to travel for games, and I am sure many of us would love to take in a game per season at Memorial Stadium, the nice new Gophers stadium, Madison, the Big House, or the Horseshoe.
Tickets cost money, and those communities would appreciate having the extra tourists coming in with Iowa license plates on their cars. Fuller stadiums look good on TV, too.
I do not know how to quantify this effect, but it would help make something up for us.