[Luca]

Better/faster transportation and instant communication as well as de-industrialization means that you tend to need fewer, bigger cities or (given Anglo-American preference for pseudo-sylvan fastness) lots of very small.suburban ones.

The information-economy-based, cool urbanites will live in mega 'world' cities and find min-sized cities provincial and thedistribution-economy-based, run-and-hide suburban crowd will want to live in make-believe Mayberries. The in-between stuff dies.

Here in teh UK, when cities liek Birmingham or Manchester actually spend money trying to advertise that they are 'cool' and 'happening' it's almost so sad you don't laugh...almost.