This post is not meant to call you out or anything, but this excuse used in Miami's case always has bothered me.
Miami's being a rotten sports city has absolutely nothing to do with weather or business meetings or people clubbing 24 hours a day, but because it is a transient city with a lot of people coming and going which results in a very static, ever-changing culture. Thus, unlike cities like Boston or NYC or Chicago or Cleveland, Miami's sports teams aren't generally passed down from generation-to-generation as a communal gathering that helps carve out the identity of the city itself.
That isn't to say that there aren't diehard Heat fans, but they simply don't number the hoards of followers in cities that are less transient and the sports teams are literally a way of life, not just something to do on a random Friday night.
The fact is, 70 percent of Miami's residents are either first or second generation immigrants. And, 40 percent are first generation immigrants.
Those are the transient statistics coming from outside the country. Throw in the transients that the city gets from around the U.S. and you get a population that is almost entirely made up of people whose families are from elsewhere.
THAT is the difference. My dad brought me up watching and attending games for all Cleveland franchises, his dad did the same with him and so on...
The sports franchises are a part of the culture in midwestern cities and in big cities like NYC, Philly and LA. You simply cannot have that kind of generational, intimate relationship between a franchise and a city when your population has immediate backgrounds from, not just all over the country, but all over the world.