"If you don’t have sufficient population and income density, you can’t support urban neighborhood retail; if you can’t support neighborhood urban retail, you don’t have any real walkability; if you don’t have walkability, you are car dependent; if you are car dependent, then you are in direct competition with the suburbs; if you are in direct competition with the suburbs, you are probably going to lose. You can’t have a walkable neighborhood if there is not, in fact, anything to walk to, no matter how many sidewalks you put in."

-the Urbanophile,
 from Density Reconsidered