The old suburban frontier is closing. Here’s what the new one could look like.

For the last half-century, America’s population growth has been concentrated in the sweltering, equal parts bone-dry and waterlogged, yet ever-sprawling Sunbelt. Undeterred by the limits of hydrology or climate, metro areas from Las Vegas to Miami have gotten one thing undeniably right. They have long led the country in housing construction, resulting in a relative plenitude and affordability that shames coastal cities in California and the Northeast, as well as a booming industry of takes imploring...