Southwest is not going "head to head" with anybody. This isnt a football game, it is the airline industry. There is an untapped resource of low-fare leisure, and small business travelers out there. Southwest's market-research people can see that just as well as US Airways', United's, American's etc... When they tell management, "we think there is a large enough base of low fare travelers in XYZ city to support our service even with our competition", then the airline will begin service there. Herb Kehler is by NO MEANS stupid. If he thought that he couldnt make money flying into a market you can believe that SWA wouldnt be there. On the other hand, if you think that the traveling public in BDL or any other city will simply abandon other airlines to fly with wonderful magical SWA...well, you're fooling yourself then too. The only "winners" in this are the low-fare travelers in BDL who now have the choice of a number of full-service carriers, along with several low-fare carriers in the region!
I have no doubt that SWA will fill up the airplane regardless of where they chose to fly from BDL. I also, however, have absolutely no doubt that Metrojet will be every bit as successful. There are a LOT of low-fare passengers in the Northeast.