[goialoq]

It's much more efficient to move people from rural areas into the cities, than to build micro-cities all across the country.

[elihu]

Much of our civilization depends on food and natural resources that come from sparsely populated areas of the country. On top of that, real estate and rent are ludicrously expensive in most of the nicer large cities. It makes sense economically for people to spread out if they can find the employment, education, and services they need in smaller towns.