Not only a matter of environmental concern (think of the resource demands, and the waste), but an alarming outlook in terms of social connections and community:

More than half of China’s existing residential structures will be demolished and rebuilt in the coming 20 years, according to a senior researcher from the Ministry of Housing and Urban-Rural Development, a claim that has sparked fresh questions about the short lifespan of Chinese buildings.

via ‘Most homes’ to be demolished – Nation – China Daily eClips.

I haven’t begun to research the social impact of even temporary displacement yet, and this outlook constitutes something more like “community in disaster,” a subject that has got some attention, after Hurricane Katrina, for example.