Not a great comparison...
Love field is still within very close proximity to downtown Dallas. Ditto for Midway and Chicago. Transit in and out of those respective cities from their secondary airports is very easy.
Stewart is about 70 miles out of Manhattan, which translates to ~90 minutes by bus/car as the most direct route. The train options are not convenient, though possible if one doesn't mind more hassle and longer door to door travel time.
If SWF was a great alternative for New Yorkers, there would be more than just a few flights on DL, AA, JB, etc. It's main draw will be residents in those far Northern reaches of NJ, NE PA, Western CT, and the Northern parts of Westchester county and Putnam Valley. We can't keep looking at this as a JFK/EWR/LGA alternative because it's simply not.
It will be interesting to see how Norwiegian does now that they've started ramping up service from SWF to thin Europe routes. If they remove future flights from the schedule after this Summer, then this becomes an even more difficult venture for USGL.
