I suspect this is employee burnout from repeatedly seeing their coworkers laid off and being told to "do more with less."

The airlines -- like all other MBA-run businesses now -- are titrating their services: They cut staff and pay and quality until customers start to loudly complain or leave and then they restore just enough staff or quality until the shouting stops.

They do this repeatedly in a closed feedback loop. Any CEO that doesn't work this way in the modern era gets fired.