[LMich]

LaI'm not so sure that's a completey accurate prediction. Much like Pittsburgh, I'd suspect because of the hilly topography, Atlanta will develop some very dense nodes of urbanity. Houston may be able to develop more uniform density across the board, but hilly topography kind of forces super urban nodes.

Still, with our dependence on the car, and how auto-oriented many of these cities are built, we're decades off from that. For some of these newer sprawled cities, it's going to take a near complete reworking of transportation infastructure (i.e. the streets and highways) for them to fill back in on a human-scale, and, that's even if they want to do that in the first place. Who knows, many of these cities may simply develop commuter rail systems, and simply keep stretching them out for even further flung counties, allowing more sprawl.

I mean, I took at a city like Las Vegas. At 131 square miles (some of which is mountain), and 591,536 (2006 - City of Las Vegas Estimate), it gives you a pretty respectable population density of 4,508 ppsm for a new sunbelter. But, it still functions as nothing more than a collection of dense suburbs, and will continue to do so for the forseeable future for the sole fact that, in order for it to function as an urban city, the infastructure would have to be completely reworked to transform it into something much more human-scaled.