There are many reasons to dislike this economic recovery: it has been lumpy and unevenly distributed by geography, by industry and by level of educational attainment. Much of that has harmed people who were once considered middle class. Add to this the decades-long impact of automation, globalization and the decline in labor’s bargaining power, and it adds up to economic stagnation for the middle class.
https://www.bloomberg.com/view/articles/2017-02-15/the-middle-class-squeeze-isn-t-made-up