I think I remember an analysis that said Detroit just about broke even on what they spent versus the economic boost to the area. Of course, it is impossible to quantify in dollars what the city reaped in good press... But whatever benefits Detroit received in good press were clearly short lived.

I would be more in favor of Detroit pursuing an Olympic bid. A successful bid will force Detroit to make some quality of life improvements that would make it a more viable place to live overall. I don't think hosting the Super Bowl is enough of an incentive for the city to do those things. But the city can tout it's successful stint as previous host city for the Super Bowl as evidence that it could handle the Olympics...