Cities do scale, but the low-density "Suburb City" that describes large parts of the US doesn't scale feasibly because the property tax / sales tax per square foot of property is insufficient to cover the city infrastructure to maintain it. The answer, unfortunately, is more growth, in an almost ponzi-scheme like fashion; new property tax revenue covers the cost of replacing roads and sewers from much older districts of the city and so forth.
You can see this in how cities tend to go full blight very quickly after the jig is up (e.g. Detroit, probably the largest example, but many midwest rust belt towns too).
I live in a "semi-rural" part of a European country between two major cities and I'm surprised at how immaculate the arterial road is that I live on, between the cities (kind of a "country road" that parallels the highway). Where I lived in the US before, similar roads were full of wheel-eating potholes. But then again, property prices here are through the roof because the government heavily regulates growth, so that's where they get the revenue.
You can see this in how cities tend to go full blight very quickly after the jig is up (e.g. Detroit, probably the largest example, but many midwest rust belt towns too).
I live in a "semi-rural" part of a European country between two major cities and I'm surprised at how immaculate the arterial road is that I live on, between the cities (kind of a "country road" that parallels the highway). Where I lived in the US before, similar roads were full of wheel-eating potholes. But then again, property prices here are through the roof because the government heavily regulates growth, so that's where they get the revenue.