Working in and around Baltimore and DC, I see the advantages and disadvantages of both spread out development (suburban sprawl) and a centralized business district linked to the surrounding area by a growing metro rail system. Part of my job is servicing equipment in the poorer sections of Washington, DC, where people apply for public assistance, and invariably those offices are at about the furthest populated point from a Metro stop you can find in the district. On the corridors that Metro serves, the city has an air of vibrancy and prosperity, they are advertising million dollar townhomes in Bethesda, near a Metro stop. The areas poorly served are areas where you want to be out of there after dark. Even in these areas, parking is at a premium,
DC has some of the worst traffic in the nation despite this, due to centralized business districts, and the necessity for cars and trucks to drive around delivering goods and provide services to people and businesses in the center of town and in the edge cities as well. Out in the edge cities, major employers often have campuses which have no metro stops, large parking garages, and if they are lucky, a shuttle that runs occasionally to a Metro stop. Throw in DC's status as a major tourist destination, and you have a Beltway and major radiating arteries that can be clogged at any hour of night or day.
My thinking is that there is an optimal size for a city, if it gets too large the infrastructure needed to move all those goods and people around increases exponentially, which is why it costs so much more to live a certain standard of living in places like NYC/DC/LAX/CHI/SF than it does in places like Cincinnati or Omaha. That optimal size is affected by the opportunities available in a given area, versus the cost of providing adequate infrastructure to serve an area. Basic Econ 101.