The way I read the BTB statistics, in the last year or two, on the average day of the year there have been around 1400 visitors on the island. More in March, fewer in October.
This includes both "real" overnight tourists and folks who own houses, condos, etc. on the island and just come down for a couple of weeks or a few weeks a year.
In the entire country, from Corozal to PG, Belize City to Benque, on the average day there are only around 4,000 visitors in the country. (And fewer than 700 overnight tourists arrive on the average day, by air, land or sea.)
Where are all these South Beach people (and other new proposed or under construction projects) going to come from? Is tourism to Belize plus second home purchasing in Belize going to suddenly go ballistic and outperform all historical norms by a factor of 5 or 10 or 20?
Kinda hard to see it.