[asynchronous13]

"Add in the population of the surrounding suburbs and the number jumps from half a million of over 6 million. If all of us lived in the city, not only would it be even more overcrowded, but it would collapse."

Not at all! If everyone in metro Atlanta moved into the city proper, the population density would still be less than that of Paris, France.

Paris Population: 2.2 million, Paris Land Area: 40 sq mi, Paris Density: 55,000 per sq mi,

Atlanta Metro Population: 6 million [wikipedia says 5.3 mil], Atlanta City Land Area: 130 sq mi, Hypothetical Density: 43,000 per sq mi, (Actual Density: 720 per sq mi)

[rayiner]

As they say, you can fit the whole population of the world onto Manhattan. That is, of course, besides the point.

Atlanta is completely unequiped to handle that population (infrastructure-wise). It's not even clear that building out that infrastructure at that density would be wise. It's costly to build infrastructure for a city as dense as NYC. The cost of the subway system dwarfs the cost of running water and sewage piping to suburb. It makes economic sense in NYC, because space is at a huge premium. That doesn't necessarily make sense for Atlanta, a city with no natural boundaries and surrounded by cheap land.