Even within cities, levels differ from place to place with respect to economics, ethnicity, and gender. Cities both push populations towards rising levels of literacy and simultaneously push them away. Usually, although not always, they do offer more opportunities, print is more ubiquitous, and work is available. On the other hand, cities often have overcrowded institutions, and fewer and less adequate ways of surviving. Evasion of compulsory schooling is easier, and at least in contemporary North American cities, it is easier to get information by means other than print.
Literacy is neutral and beneficial.
No mode of learning is neutral. There are always biases with respect to transmission, e.g. the textual bias of school literacy. In making explicit written prose the model of literacy, we have downgraded the other modes of communication. Most of what we mean by school literacy involves a narrow conception of decontextualized words. Overvaluing alphabetic literacy has had massive human costs.