Well, Miami is hot and sunny for most of the year. Of course, there's the occasional hurricane, but we get Nor'Easters.
Miami beaches a built out like that because of demand for beach living in Florida is so high. In Massachusetts, all the nice beaches are either conservation land, or the prices are so high that only wealthy homeowners can afford to build on them. Of course there are exceptions, but I don't think that Revere Beach can be rightfully compared to South Beach, even though geographically, they're quite similar.
I agree that Revere Beach should be developed, though. I'd live there if it were a little bit less seedy.