I think you may be neglecting the extent to which you are describing the self-reenforcing downsides of "post white flight" urbanism. Given the age demographics of HN, it's more likely than not that the city life you (or any of us) experienced was well after white flight ran its course, with consequent effects on crime and noise in cities. If you imagine a world in which the people who wanted quiet never left, the picture of urbanism looks a bit different. If you read about American life in pre-war cities, or the late 19th century, urban areas were a place where all types of people lived, including families, the elderly, and people who seek calm and quiet.