Solve the problems of city living. Crime is higher in cities than in the suburbs, and government schools are often worse than their counterparts in the suburbs. Of course, the problems are diverse and complicated. Libertarians call for lower tax and regulatory burdens, which will increase economic prosperity and opportunity in the cities. Libertarians call for the repeal of drug prohibition, which will reduce gang violence and put street pushers out of business.
Libertarians also note that city laws which disarm the citizens give criminals the advantage.
If city life were better, fewer people would move to the suburbs. Our choice is between market growth and political growth. If we have more of one, we necessarily get less of the other. The more power politicians and bureaucrats have, the less power individuals have to cooperate voluntarily using market institutions. Too often, debates about growth merely pit one sort of political growth against another.