Miami is a COMPLETELY different market. It makes absolutely zero sense to compare these markets. Miami is a place where only about, what, 20% of the population was actually born there? The majority are transplants from other states, or worse, immigrants (by worse, I don't mean anything racial, I mean it's worse for a sports business that isn't as popular overseas as other sports). Places like GB and Buffalo don't have this problem because nobody wants to ****ing move there. Harsh, but true. So, with Miami, you have a weird situation. You have a bunch of people that were born there that moved away for work or because times got to tough and they had to move on (same happened in every market that was hit the hardest, such as Phoenix) and you have a bunch of transplants and immigrants. This is one big reason why the team remains popular nationwide, despite a decline at home.
The market is still there, but it's a different kind of market. This is key. There was always a market in places like Phoenix (I keep using them because I lived there) despite it's huge transplant population, however, nobody showed up to those games because it was an absolutely horrible product. Then, suddenly, they started winning. What happened? Miraculously, fans started showing up. The stadium was selling out. Part of this had to do with it being a new stadium, but that won't be enough. That stadium is in the middle of ****ing nowhere. It was literally surrounded by farms when it was built, so once that team starts losing regularly again, that attendance will plummet.
That's just the market. Ridicule the fanbase all you want, it just means you don't have a clue about how this kind of business works. That's like Borders bashing customers for not wanting to pay $30 to carry bricks around anymore rather than adjusting to what the customers actually want. In this case, the customers want a winning team. Once that happens, then they can start rebuilding a larger foundation of diehards that will stay loyal during dips in competitiveness, though that will never, ever last long in a market like Miami. The fanbase turnover is too great. Once they start winning consistently, the average fans will begin to turn into diehards, as will their kids. Anybody that grew up in Miami during the 70's, 80's and most of the 90's knows what that is like.