I don't disagree with you... but I would be surprise about other airlines at this point in time. And yes, STT could be a problem, depends on pricing. But the Eagle flights I am not sure is a good indicator. Reason is that they did have multiple flights from SJU per day, smaller planes (puddle jumpers). When you get to one flight even every day then the options and load become complicated for the airline. You have to get the people to the connection, get them onboard and landed, turn the plane around with a full load to make the connection back to their home.
If bvi subsidizes then that is different, but for how long and how much. Have seen it before on many destinations. Daily then drops significantly later.
But it also has to do with accomadations, yes there is a lot of bed space on BVI, but not compared to many of the other islands, and specifically to USVI. You have major chains, etc., that offer vacation packages, etc. that really do not exist in BVI... but BVI has a major charter industry yes, but they are not going to be offering vacation charter packages would be my guess.
I can hear the hoots and howls now about cutting my charter short or having to spend $$$$ to extend because of the direct flights -- so then they take the STT flights and ferries and the demand is not there again, so the airlines say forget it. Being pessimistic/realistic, but the runway alone is not the answer to the airfare/flight issues with BVI. I think that there are many other issues that will also have to be addressed to answer that question.
