Annie Lowrey of The New York Times Magazine reports:
This is in part a result of the decline of manufacturing and the rise of the service economy. Heavy industries like steel making tend to cluster in certain parts of the country, whereas services like fast-food sales, pool cleaning and day care tend to blanket it. Even in the heyday of American steel making, a smelter operator’s job search was rather limited geographically. Today, a day care worker can look for a job anywhere — and she would probably be able to find one close to home.