I was reading the November issue of ODE magazine and came across a letter to the editor in response to an article about how people fulfill their dreams in cities. The letter said, in part, "cities are unsustainable living areas, as they swallow up resources without being able to offer anything in return." The age-old bargain of civilization is that the countryside supplies the city with natural resources and in return, the city offers culture: art, literature, theater, architecture, philosophy, religion, even government. Cities still do that. Natural resources may hold more appeal for the letter writer than culture, but it is wrong to say that cities offer nothing in return.
I've never seen any statistics, but I suspect that on a per capita basis, cities swallow fewer resources than rural areas. Cities have more expensive roads, but far fewer of them for each thousand people; mass transit and walkable distances reduce the amount of gasoline used by each person; community waste water plants are easier to keep from polluting water than dispersed septic tanks. Urban areas certainly generate more wealth than rural areas (which is why so many people throng to the cities), so if the per-capita resource use is the same, cities show a better return on investment.
Besides, if everyone were evenly distributed over rural areas, there wouldn't be much room for resource extraction, or even agriculture. Getting rid of the cities wouldn't automatically make the countryside any better off; it would probably be a case of a lowering tide dropping all boats, since there would no longer be the wealth-generating cities to buy the countryside's produce, meat, and resources.