CAPA - Spirit and Frontier add new ULCC competition in Atlanta, will Delta or Southwest feel the most heat?

Crazy thought: Instead of beating one another about the head and neck, what if Frontier and Spirit cooperated to compete against WN and Big 3. Since the Legacies won’t allow us to re-book stranded pax on their flights etc, what if Spirit did, and vice-versa? Not suggesting a merger or anything, just some synergies that would be mutually beneficial to both of us. It seems foolish to compete head to head with our ‘sister-esque’ airline when we’ve been told ad-nauseam that together we only make up 1/10th of the untapped ULCC potential in America. You know as compared to Europe? Just a thought – feel free to set me strait. NK guys please chime in too.