Yup. I actually think the world is ripe for the return of city-states. The advantages of nation-states have fallen in importance, while their disadvantages have become increasingly clear.
Just look at the success of Singapore to see how effective a modern city-state can be. London, New York, San Francisco, etc. would all be better off as independent self-governing city-states.
Just look at the success of Singapore to see how effective a modern city-state can be. London, New York, San Francisco, etc. would all be better off as independent self-governing city-states.