Context : OnCities
I suppose this is the shadow lurking behind FallingApart.
A simplification :
The rural economy is based on exploiting natural resources. (Farming, mining, oil etc.)
: markets are problematic for the rural economy, because those exploiting natural resources are encouraged to maximise throughput, and so the market accelerates consumption until the resource runs out. Markets can't produce the right signals to encourage "husbanding" of, or preservation of, resources. (And AgricultureMistake)
The urban economy is based on trade or creating new connections (applying new ideas to the shaping of resources in factories, various co-ordination innovations planned in head-offices etc.) In a sense, urban economies are based on creating wealth out of human labour and creativity. (CreativeClass)
OK, I know, I know, this is an outrageous simplification. :-) I know perfectly well that it's all those new ideas created in towns that are sucking in the reseources from the country, so the work in the cities is accelerating the consumption of natural resources, but still ... there's something here.
Anyway, there's the hypothesis ArgueAgainstMe (except you'll have to send me an email if you want access to this wiki.)