Its seems to me the 3 legacies (and now B6) do seem to be very aware of the ULCC even with the huge difference in market share. Otherwise why would AA, UA, DL and soon B6 gone to BE? Admittedly it gave them justification to make their lowest fares even more restrictive. Personally I'd wish the entire ULCC business model fall flat on its face but the opposite is occurring. Some (including Chase Bank) are anticipating a major economic downfall in 2020. If so, will the airlines of carrying leisure paxs see a major nosedive in demand. Remember back in 2008/2009 when AA (and others) were doing things like 2-3 a year DEQMs to rouse up business? What's Spirit going to do other than cut capacity and routes, park planes and fire staff? Usually given the high capital costs of running an airline that doesn't work.