This seems like a strangely theoretical argument, as if the world outside America simply does not exist.

Isn't the article about college towns in America? It's not theoretical there.

A more universal example is probably towns with large seasonal influxes, such as ski towns or beach towns, but unlike a college town, these locations attract people of all ages and incomes. College towns in the US have an influx of specifically 18-22 year olds who can afford college but might not have a lot of disposable income, and most leave during the summer.