SWF, as well as ISP
have no high-yield business travelers. Those markets, along with HPN
are cheap, cheap, cheap tickets, and the major carriers are finding other routes where they can make money with their equipment.
Even if SWF (or another regional airport) makes a little bit of money, it makes sense for the airlines to move the planes/routes to where they can make more money. That is the state of the industry these days, and I can't see that changing anytime soon...
"Keep thy airspeed up, less the earth come from below and smite thee." - William Kershner