I posed a question about this to friends of ours that are in their 5th year of cruising the Caribbean, currently at anchor in Rodney Bay waiting a favorable window for a passage to Martinique, their answer:
FWIW...I cannot speak for US boats outside the Caribbean, but as we sailed south of the Bahamas, US flagged boats were few and far between until we reached the EC where we began to see higher numbers. No matter where you sail you will find cruisers who have "found a home", some year round, others seasonally. There is a great variety of boats to be seen. Most older Americans do tend to sail the typical "cruising boat; the Westsails, the Perry designs, etc, are prevalent, but, there is a higher number of "performance cruisers". Older Tartans, Benes and Jennies, Pacific Seacraft, Valiants, etc. Lots of Island Packets, the cult boat; people love them who own them. IP did a great marketing job with those boats. And, they are ruggedly built with quality components, but, they have just as many problems as we do. Few Hunters, and fewer Catalinas, one or two here and there. Rarely a Morris or a Hinckley. Lots of aluminum and steel among the foreign flagged boats; some wood, but not many. Lots of Oysters, Swans, Najad, Bavaria, Malo, HR's, and other quality Euro boats.
I think there are more boats sailing than parked. In Trini, one US boat is parked there; everyone else sails. In Grenada, there are more parked US boats, but far more boats sailing. This is our 5th year here, and we've visited all the "popular" spots, and many "out of the way" spots. We prefer the "out of the way" locations. The only locations where cruisers park for the season are the major ports and harbors, Chaguaramas, the mecca; Prickly Bay; Clarks Court; St Georges; St. Martin, and other similar. I guess your [poster] has yet to visit the "out of the way" places in the Caribbean.
Much to our regret, we did not stop in St. Vincent this year; time and weather and our timid buddies. another time maybe. It is a beautiful country that has a poor reputation, yet several charter companies have bases there. So what does that tell you?