Miami IS a terrible sports town.
Yes, fans a pretty fair weather here, but no more so than other similar sports towns.
Votes for Toronto Atlanta
Plus we have a disadvantage because hardly anyone in south florida is actually from south florida. There are large number of fans from New York, New Jersey, Boston who all live here now who don't support local teams because of long lasting ties to former teams.
As for the Heat, There were plenty of fans prior to the Lebron years as D Wade has been one of the highest selling jerseys in the league for years.
Marlin attendance numbers would be much higher if the entire town didn't hate the franchise for the stadium fiasco