I already pointed out that the Bears don't seem that interested in going to Indiana. The location is not central to their fan base. They will not be able to control the entertainment dollars around the stadium the way they would be able to in Arlington Heights, or even in downtown Chicago. It simply is not the best deal for the Bears, unless Indiana just starts throwing rediculous $$$ at them that so far it has not done.
The infrastructure improvements that you point out are a real issue. Indiana's governor claims that the state is ready to provide what is needed, but let's see what happens when residents are asked to pony up for that.