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.