JB doesn't "need" NK. NK brings both solutions and new problems. There are solutions without NK, just would take money and time. Of course management wants the easier/faster solution. In it's absence, they will have to take the longer road. But will avoid the problems.

JB has large loyal customer bases and large slot and gate portfolios in places that are basically unobtainium to new entrants. The ULCCs can't even make daily and full year service work for much of there network, and have almost zero large metros (where the well funded FREQUENT travelers are) where they control anything approaching a large proportion of local traffic... They can't even afford gates in Denver anymore and are switching to hardstands (Frontier).

JB will either improve it's offer and win (appears less likely) or move on to plan B (which was plan A just a few weeks ago).