You might have something there...
A quick look at a list of Superbowl winners show that most, if not all of them, seem to hail from the "blue" section of the famous "Bush Country" map, although I have only given it a cursory look and have not actually connected county borders to exact city locations. Maybe football winners do tend to become liberals, or maybe it's just that liberal cities have an easier time soaking taxpayers for the fancy stadiums that attract the good teams.