You're less coherent than usual in this post.
As Todd points out below, rural areas have the same kinds of people that urban areas do. With the same problems.
Your third paragraph is a true-ism. Yes, if you want to kill a lot of people quickly, well you need a lot of people in a relatively small place.
Decentralization is the wave of the future. It's just a matter of getting that last mile problem completely licked. We'll still need port cities, but no one will have to live in them anymore. We'll just have waldoes for dockworkers.
You need to elaborate on that a bit. It sounds rather Pol Pot-ish to me.
What time frame are you talking about?
I think that for the forseeable future (say the next 20 years) cities will continue to grow, especially outside the US. In the vast majority of the world, the best way to increase one's income is to move from a rural area to a city. It's been that way for a long time, and I don't see it changing.
And who's going to build all the roads and airports and drive all the trucks to have the cities emptied? Who's going to build the power plants, put up the power lines, dig the sewer lines, etc., for this? Or do you imagine the population of cities simply disappearing?
I hope you're not imagining some [link|http://www.agclassroom.org/teacher/history/1820.htm|1820s agrarian utopia] or something. A time when 300 hours of labor was required to produce 100 bushels of wheat, when the US population was < 13 M...
Cheers,
Scott.
