Consider the Tiger's in light of the Marlins whining:
1. Downtown Detroit is not exactly an attractive place to drive to in your car to at night. In fact, it makes the neighborhood around the OB look like Grosse Pointe
2. There is a large casino pretty close ( I would think less than a mile, although I've never walked it) to the Tiger's stadium. So, it's not like there's no local direct competition for entertainment dollars.
3. In 2003, the Tigers average attendance was 17,100 per game. That was in the new stadium. In 2007, the Marlins attendance was 16,900 per game. When the Tigers hired Dombrowski and started investing in players, they got better on the field, and sure enough, their attendance began to improve--in 2007, their attendance was 37,000+ per game. They didn't get a new stadium, they got a better team.