Is rural even a thing?

 Most places that claim to be rural aren't. I'm not even sure I believe in 'rural' as a construct. Where there are people, urbanity follows. Any time you get enough people for trade to exist, a central place emerges. And once a central place emerges, more things cluster around that. Once congestion/land values in a central places becomes too extreme, you get sub-centers. 

In an industrial society, subsistence farming just isn't a thing. Once manufactured goods exist, a farm needs to export something to make the money to purchase goods. It's a continuum of how much of farm production is devoted to local subsistence and how much to export 'cash crops', but once capital production equipment provides even a marginal advantage, specialization happens pretty fast. Someone buys a plow, and they specialize in field crops, and that's the end of orchards for them. 

So the actual traditional pattern in America isn't 'rural', but rather small towns. Places for the retail, repair and maintenance of manufactured goods, the provision of specialized services, and 'congregational goods', that can't be enjoyed privately, like church services and festivals. 

So what's the difference between a town an a city? Is it just when a town gets bigger? You might argue that it's just a difference of degree, that if a town gets big enough, a scale dependent transition takes place, and it becomes a city. I'd argue that this is bunk. Central Place Theory aside, a city is distinct from a central-place for central places. Fundamentally, what makes a city is trade. Every city* sits on a transportation nexus: a natural harbor, at the convergence of rivers, the union of railways, an interchange of highways. A city gets its start at the most accessible location, regardless of how terrible that location for future development (ie Pittsburgh). And where there is trade, ware-housing follows. And once materials are warehoused, it's only natural the industry (processing materials) and manufacture (combining elements) follows one the same site. Pre-mechanization, industry requires a big work-force, which means a lot people, which means a lot of housing, which means a lot of furnishing, in a parallel urban development cycle. Post-mechanization, industry and manufacture require a specialized/skilled workforce, which means high wages, which supports all sorts of secondary consumption, which drives further workforce specialization. 

*Administrative capitals being their own weird case. Salt Lake City also an interesting case. It was never intended to be a city, being rather designed as a 'super-town' of an agrarian/fundamentalist religious commune. Didn't work out. Even as remote and wrapped with mountains and lakes as it was, it still sat the crossroads of Emigration canyon and the Jordan River. 

Urban Ideology in America

Post-zoning, urbanism goes to hell, and there is rhetoric about the 'extinction of walking', and the assumption that everyone will drive everywhere, and walk no further than across a parking lot, and that there will be parking skyscrapers as-needed. And that ideology prevails until the 1970's, when the 'Urban Transportation Problem' gets published/realized--it's impossible to 'build your way out of congestion'. Also a general realization that the 'share automobile' of buses for non-car owners isn't financially viable (on a per-mile basis) in suburbia. So you get a decade of 'cars plus commuter transit' (BART, WMATA, MARTA) when it's realized that those cost too much to build out the planned network, and it takes until New Urbanism until we have an alternate ideology. While we're waiting for CNU to rediscover walkable urbanism, we're stuck with crank Modernist city planning, the rational comprehensive model, Brutalism, traffic-based transportation investments, and similar bunk.

The Legacy of Prohibition

As a culture, America has minimal capacity for multifamily urbanism. We used to know how to do it, then we made it illegal for so long we lost the know-how. And the infrastructure, and the institutions. And so to do it again, we have to reinvent it all over again. We have to change the laws, build the infrastructure, develop the institutions. It's slow going.  It's like Prohibition, when we banned alcohol. Except that the ban has gone on so long that all the former brewers are dead or retired, and banks no longer know how to estimate the risk of breweries, so they won't fund them, and cities still won't permit them to locate within city limits. Oh, and anyone who buys a bottle of non-alcoholic juice gets a 10% discount from the Federal Government, and doesn't have to pay sales tax.  

Competing Urbanisms

Attached housing is a different way of living than detached housing. Shared systems means reliance on communal assets, and hence some governance method for managing those communal assets. If you are poor, and your neighbors are trashy, there is an insoluble communal action dilemma, a veritable prisoners dilemma. It only makes sense for you expend effort cleaning up the central lawn if everyone else does it. In cases like bungalow courts, the number of people involved is small enough that the small-group dynamics habits evolution has hardwired into humans can work it out. As the number of people increases, individual agency is diluted, no one is responsible, and you get The Projects.

*Arguably, attached townhomes would work...but most 'townhomes' are actually condos, from a legal/governance setting, with a condo board, so they have a method of managing communal assets.