"The real problem in the ever-mercurial global economy is how to manage cities whose roles in it could become unmarketable by next week. The urban theorist Richard Florida argued in the March Atlantic that the answer was to redesign our urban geography for increased mobility. That way people can keep up with changing job markets and members of Florida's lionized "creative class" of white-collar professionals can find one another. The old system that encouraged home ownership should be jettisoned in favor of renting, which makes it easier for people to pick up and move without the time consuming agony of home selling. Cities should be more concentrated, less suburban, and more connected by public transit. I'm generally fine with those propositions, as are most urban planners. However, there are bigger issues at hand when we talk about enhancing mobility to accommodate the volatility of unleashed markets."