That's the issue. The LCC's are banking on the legacies gifting them capacity, or at the very least forcing someone's hand with merger mania to buy off a competitor.

A year or two ago I would have been very concerned the legacy airlines (very much including SWA) would have yielded to the young buck marketshare poachers but the tide had apparently turned. Legacies have hit critical mass where they can bury an insolent LCC or two (each) on any and all competing routes and still post big profits over all.