Romeo Santos has millions made inside the Spanish speaking world. I bet nobody in Nigeria has ever heard of him.
There are certain markets that for whatever reasons (economic development, cultural and/or political constraints) certain types of music do not penetrate.
What sets a certain type of music apart these days is the type of money available in other countries to touring artists. Now that everyone downloads and otherwise copies music without paying for it, the money for recording artists is in touring. That money used to go to the record companies, but their power is waning to the point where they will no longer be needed for an artist to put out music.
It is therefore impossible to gauge a music's popularity in certain markets judged solely by record sales or a couple of people dancing to it in some faraway country.
An artist like Romeo makes good money due to a couple of converging circumstances-the need for a Latin heartthrob in the Latino community coupled with the fact that his genre is bereft of competition. He's been able to make good money in the markets that matter-The United States and to some extent Western Europe, where the real money is. Anything south of the border is gravy for him, and that gravy is strong for him right now.
But none of these are the reasons why Frank Reyes wants to leave to Miami, because he's not an artist on par with Romeo. It could be anything. Maybe he wants the quality of his day-to-day life to improve. Maybe Reyes is tired of family members mooching off him. Maybe he's being extorted. He can still perform in the DR if he so chooses, and where he lives has no bearing on where he chooses to perform.