The model worked for years, but maybe it doesn't work at scale. I'm not an expert, but looking at random DFW to LAS flights, Spirit is $50 ($100 with a bag) and AA is close to $400. I think it is mainly things outside of the model that are killing the company. I'm just saying the people melting down because they have to pay $150 for a bag should have taken the ample opportunity to buy it ahead of time.