In other disciplines to leave your
university because another offers to pay you more entails personal humiliation
and status degradation to a not inconsiderable degree: you are supposed to value
ideas and colleagues and students, not cash. In economics, however, the thrust
of the discipline makes a failure to respond to market forces a moral fault in
Brad DeLong explaining why public universities are having an especially difficult time hiring and keeping economists now that the privates are boosting salaries to a tremendous degree. Experience at GMU is consistent. See David Warsh (here and here) for the backstory.