I am it saying anyone won't open a base in SJU.

AA used to control SJU, but they slowly have pulled away as MIA grew. As the airports in the Caribbean expended their facilities AA slowly pulled away from the T-prop and more 737 our of MIA. AA during bk returned most of their gates and as far as SJU is concerned, it's a ghost town for AA. Let's say that someone was to place 76 seaters in SJU to feed AA, I am not sure how they would fill the airplanes as AA has drastically decreased the amount of flying done in and out of the island. Right now AA bring people to the island and for cruises, the minority are heading to the small islands that AA can't feed from the US. Now I could see AA possibly do 76 seaters from MIA into some of the islands, but a large RJ base in SJU would require AA to transition flying from MIA to SJU and with everything that it's being said I don't think that's going to happen.

Right now AA doesn't fly enough passengers to SJU to fill 76 seaters and spread the pax around the Caribbean.