Yes, those areas can sustain some communities, but not the massive development that's been going up.
I wonder what are the safest parts of the country to live in as far as natural disasters go.
The Gulf Coast and the Atlantic from Norfolk to Florida are threatened by hurricanes; any city on the Pacific Coast, including Anchorage, could be flattened by an earthquake; Phoenix and Las Vegas are growing rapidly in land not fit for humans, and could run out of water.
In the rest of the country, you can freeze, lose your power to ice storms, get flattened by a tornado, or suffer a heat wave, but nothing that will make your whole city uninhabitable. Nothing's ever going to destroy Boston, Chicago, Dallas, or Atlanta.
I'm not sure where I'm going with this, except that maybe we should do something from keeping the most dangerous or marginal landscapes in the country from being the FASTEST growing, most heavily-developed new cities.