I suspect other airlines might be interested. I mentioned Atlanta with Delta in mind. Delta has some 737-700's with the short runway kit seating 124. I think that they run to several markets 1 or 2 days a week with that airframe. Eagle was running 300 plus seats a day from SJU with the vast majority of passengers connections from the U.S. I suspect the market would support a daily flight for someone from the U.S.
If they extend the runway the BVI government is going to have to pull in flights or look very foolish. It would not surprise me to see them offer to subsidize a airline flying from the U.S.
The flights would have to be somewhat cost competitive with STT however I suspect people would pay at least 150.00 extra to avoid the Ferry or SJU. They would also pull down the STT loads a bit so that would factor in to a decision.
G