Why don't more people become Miami Heat fans?

I know a lot of people who became fans of the Heat after they acquired LeBron. They're filled with superstars now and will win many titles. I also used to like the Spurs before, then Boston, but now I really think that the Heat will dominate for a long time to come. For the people who haven't made the switch, why didn't the Heat become your team? You'll be on the winning side if you switch also.