There is also the aspect of this involving the cost-of-living for people in urban areas. People in urban areas tend to face higher costs from taxation due to infrastructure costs (among other things). Combine that with increased air pollution and more limitations on property rights, it’s no wonder many cities have rejected smart growth policies in favor of allowing more naturally occurring suburbanization.

I might be able to see smart growth policies work in a futuristic world where there are flying/floating transport vehicles and all sorts of other neat stuff that would reduce costs on individuals and families, minimize environmental impacts, dramatically improve land use, etc. Maybe someday, but at present it just seems that the suburban world is so much more pleasant than most dense urban environments.

http://www.popsci.com/node/46221