> The problem is that usually you still have to commute to work. Living far away from jobs means a long, unhappy commute. The unhappiness caused by long commutes is well researched - look it up if you like. People compromise and live somewhere in between, which often means the worst of both worlds.
Plenty of people do not have to make long commutes, or they choose to do so for certain reasons. This is such a generalization that it's not very useful.
More interesting would be solving the problem of people needing to commute in the first place. How many of those jobs that people commute to actually must be done in the place they commute to? And I don't mean telecommuting, I mean, does that business really need to be located in that city? In the case of many office jobs, they could be located in smaller cities to begin with, so people wouldn't have to live as far away. Of course, this is also a nearly useless generalization.
However, I would suggest that the real problem here is, sadly, politics. How many business decisions are dictated by local laws, regulations, taxes, etc? How many businesses would relocate if it weren't for certain of these that make only a few locations feasible? And how many of those political decisions are caused by other businesses lobbying for them, whether to enhance their own advantages or disadvantage their competitors?
> Contrary to what you say, dense cities can be quiet and have isolated private space. Look at the vast single-family-home suburbs of Tokyo. The population density is high even without large buildings, and you can live without a car easily (if desired), but you have your own house with a garden on a quiet, secluded street in a safe neighborhood all within walking distance of the train that can take you downtown. Not particularly cheap or spacious, though. The noisy, crime-riddled, no-privacy-at-all hellish city you describe is common, but it's not the only possibility.
This is the exception, not the rule. And I don't think Tokyo is a great example. My neighbors have a garden--it occupies as much space as their house. What kind of a garden would they have if they lived in a single-family home in a Tokyo suburb? A window box? And they would probably pay 5 times as much in living expenses, at least.
I would suggest that most cities in the world are noisy, crime-riddled, no-privacy hellholes--at least, unless you are very wealthy. The average person in the average city can't afford to live in a quiet, safe, private dwelling. But the same person making the same money living in a suburb or small town can afford a much nicer, safer, quieter home, and nearly everything they need to buy is cheaper there as well.
> What the sibling comment says is true about social interaction in cities as well. Living in the city people have more friends, more sexual partners, attend more events, and interact more with strangers. For some that is a plus.
For some, it is. Of course, it depends on how you define "city." But many people live happily and healthily in smaller places all around the world, with families and friends and local events (ones they probably have a larger role in, as well). It's not necessary to live in a big city to have a social life or a vibrant community. People have been celebrating harvest festivals for thousands of years.