As suggested by a previous post, VS only operate to 'large' airports which can support a route via a combination of Local business traffic, local Leisure traffic, and feed/connecting traffic.
The mix of these 3 will of course vary between airports and routes....MAN-Orlando will allways have a lot less connecting traffic than a LHR-Tokyo. However, I would be very surprised if they started operating to an airport where there is no connecting traffic altogether!!
If it did happen (say an Orlando service), how many services a week could it support?