Well..You could not say cuba as of right now due to communism so they cannot turn pro but they have such amazing amatuers that when communism is over Cuba will have some massive stars in pro boxing

Mexico is bigger then Puerto Rico so its bound to turn out more fighters and not that puerto rico doesnt but Mexicans are known to be tough and alot of mexicans grow up poor and hungry and make it by fighting.

Puerto rico however imo although it turns out less fighters i think when you do find fighters that come out of puerto rico they are not all as good as mexicans but when you search hard enough you find some very special and different talent from puerto rico and its nice to see, Pr brings something different to the table imo