The glass barrier to the upper middle class is hardening (Richard V. Reeves, Nathan Joo, Brookings)

America is becoming a more class-stratified society, contrary to the nation’s self-image as a socially dynamic meritocracy. In particular, the barriers are hardening between the upper middle class and the majority below them. As New York Times contributor Tom Edsall writes (“How the Other Fifth Lives"), “The self-segregation of a privileged fifth of the population is…creating a self-perpetuating class at the top, which is ever more difficult to break into.”

http://www.brookings.edu/blogs/social-mobility-memos/posts/2016/05/11-glass-barrier-to-upper-middle-class-hardening-reeves