Santa Fe complexity theorist Geoffrey West has done some fascinating recent work that shows that cities actually get more creative and productive as they get larger (they also get more energy efficient and greener). West calls this phenomenon the super-linear behavior of cities. This is in contrast to corporations that get less creative and productive as they scale: sub-linear behavior. The long-term result is that cities tend to be very long-lived (possibly immortal, since many of the most ancient cities are still around), while corporations generally are mortal.