I would also like to point out that desiring peace and quiet is another reason people leave cities. This is, of course, personal preference, but just one month ago I was living in an high-density residential apartment, surrounded by neighbors. Now I'm in my own detached single-family house, and I could not be happier. You know why? It's quiet. I can't hear my neighbors at all. All I hear at night is the furnace clicking on and off and the occasional car or distant freight train rolling by. I cannot overstate how nice it is to be able to get an uninterrupted night of sleep on a regular basis, and on my schedule.Darth Wong wrote:The reason our cities sprawl is social, not economic or technological. People want to have their own plot of land, and their own green lawn. Do you honestly not understand why it is more efficient to have five hundred people in a single apartment building than to have five hundred suburban houses, each with its own separate utility hookups and its own plot of land?
No more waiting for the asshole next door to stop doing his dishes, or for his braying cunts of guests to go home or go to sleep for the night, because now, if I can hear the asshole next door, he's being loud enough to warrant calling the cops. No, no amount of incentive or cajoling would ever get me back into an apartment; I would actually have to be staring down the barrel of the gun.

Now, it just so happens that North America has enough available land and a pleasant enough climate over the bulk of it that such an arrangement is possible. As has been pointed out, this really isn't the optimum use of land, but I place my own personal happiness and sanity above living the most efficient life possible. I would imagine that a lot of others do, as well, else the suburbs wouldn't be popular.
Finally, I would also point out that not all suburbs are created equal. It is possible to have a suburb of fairly high population density; the town in which I live boasts an average population density of nearly 7,000 per square mile, or 2,500 per square kilometer. Most of that is single-family housing, with a few garden-style apartment complexes. A typical lot size, like mine, is between .13 and .18 acres. At densities like this, commuter rail and bus networks are commercially viable, and downtown is reachable via foot or bike. Of course, these are old suburbs, built up back in the twenties and thirties. Modern suburbs make it almost impossible to do anything in a reasonable amount of time without driving. But, it is at least possible to strike a balance between ultra-high density urban life and hideously wasteful suburban sprawl.