My bad with Houston. I must have been thinking of Dallas. The factor with Las Vegas and Phoenix are that they are modern growth cities. You don't need a deep

My bad with Houston. I must have been thinking of Dallas. The factor with Las Vegas and Phoenix are that they are modern growth cities. You don't need a deepwater port to facilitate growth in a modern city, just a good airport, good road/rail links and good communications infrastructure. You could argue that Phoenix is propelled by retirees and golf players and Las Vegas by gambling - but the reason doesn't matter, just the fact that a city can be sustained does.