This year, people are talking increasingly of the "hourglass" model of cities, where all but the most financially successful (called the "knowledge/creative class") can live well. Those who would otherwise be middle class ("blue collar class") can't afford the cost of life and are pushed into a lower level of economic well-being (with the "service worker class") or chose to leave the city for the suburbs or elsewhere.
The idea is that cities become more and more just for the rich, while the rest are forced out of town because they can't afford it.
Source: https://thespeakernewsjournal.blogspot.ca/2017/06/the-hourglass-economy.html
