Spirit Airlines Begins Orderly Wind-Down of Operations [pdf]

I don't see that at all. There is certainly a multi-causality/multi-maintenance problem here but in a grossly capitalist market, Spirit's ability to thrive was curtailed not only by social presence (they're the Jet2 of America) but by an inability to function in a lean business model like Ryan Air (an exemplar of what Spirit Airlines COULD have been). M&A isn't always the appropriate exit mechanism. We have Breeze (small market), Frontier, and while Southwest has certainly exited the "value" end of the market, it still dips its toes in the water. Also, the prime carriers "Basic" tickets certainly ape what Spirit tried to do...albeit with better access and scheduling.