Someone had a theory that traffic congestion simply rises until it is intolerable. If you add another lane to a highway, for instance, the traffic eases momentarily until people start taking advantage of the improvement to accept jobs that are farther away. I guess it could be called a variation on the "Peter Principle"

If metro areas are now saturated, it seems that the time is ripe for some brand new cities to spring up. A large manufacturing company could make a killing by buying up a bunch of land in the middle of nowhere and building a plant in the middle of it. People start moving into the area to work in the plant and next thing you know they're complaining about the traffic

Then the company could start selling off the property to the gas stations and big box stores...