Except it's not at all due to urbanization. I would say it's more due (in part - the causality goes both ways) to the suburbanization in which the American ideal became to live in a big empty houses in the middle of nowhere with giant flat empty stretches of grass between you and other people.
Young urban Americans are some of the few attempting to buck this trend, which the boomers heartily embraced.
Why Americans were choosing to get away from each other when say, their counterparts in western european haven't been, and aren't living anywhere near such isolated, unhealthy lives, is a question worth asking.
> Why Americans were choosing to get away from each other when say, their counterparts in western european haven't been, and aren't living anywhere near such isolated, unhealthy lives, is a question worth asking.
Indeed. When Lisbon was expanded in the 1960's the new neighourhoods were laid out so that people could walk to their local church and primary school. The model post-war development in the US was Lewittown. My theory is that it was the availability of cars that caused the difference. I do not think "white flight" (read: unskilled labor) played a part, both Portugal and America experienced urbanization in the interwar period.
I can't speak about Lisbon as I'm not from there, but up north in Porto and surrounding areas, there hasn't been much planning at all. I live in a town (Ermesinde) that in 15 years went from less than 10,000 people to slightly less than 100,000. The only planning was: build as much as you can, even illegally. About 15% of the new buildings around 2000 were actually against the law (not following proper distance from others among other zoning problems) and were mostly approved based on kickbacks to gov officials. My parents were asked for these 'gloves' from officials when rebuilding some of their old apartments, and my own house wasn't licensed correctly to live on (I bought it used, previous owner/builder didn't obtain the licensing, had to do a lot of construction to get it to code. Talked with the lawyer, he saw the name of the person that signed the papers, said it was common for his work to be illegal as long as he was paid under the table)
I can guarantee you that denser cities also suffer from loneliness (with the caveat that a minority of all lonely people love their independence and enjoy living by themselves). It's not uncommon for seniors living in high rises to have been dead for weeks or months before the neighbours notice the smell. I don't think physical proximity is the core of the problem.
But we have a second car and only $18k in credit card debt.
The same thing is happening to societies that are experiencing urbanization. Not sure for how long this can go on...or what happened next.