I'd have to side with LuvJockey. I personally think Southwest is the type of corporation to take nibbles and small bites here-n-there strategically...Denver, NY City, Boston and sure up those markets so that the average fares are obscenly low. Consequently, if the legacy carriers do make a return it will be at the cost of a bloody nose.
IMHO, Southwest, is not the type of corporation that will take big, gulping bites at the industry (buyout of Air Tran) especially during this minefield-type environment...one misstep may prove disasterous.
Just my two cents worth, your mileage may vary,
FF