From post on Urbanophile.com:
"What is greenfield economics? This is simply the set of conditions that flow from building on new territory or exploiting new markets vs. redevelopment of old places, organizations, etc. Being able to start with the proverbial blank slate enables a huge number of benefits."
Among these benefits, according to Aaron Renn: everything is new and state of the art, no legacy costs, no legacy institutions and culture, scale economies are in your favor, few low-income residents, and ability to defer infrastructure costs.
"You might say that this is a transitory state and the problems of the city will eventually hit the suburbs as well. Very true. And indeed, that's what we see."