I don't agree with Turchin's thesis that the US is in trouble because it's producing too many elites who don't have places in upper society. If anything, America's elite problem is under-competition rather than over-competition.

American elites don't compete with each other in any meaningful way; they conspire with each other to exploit the public. Notice that nominally opposing businesses both funded California prop 22 to entrench the right of these elites to under-pay their workers. This kind of elite collusion is endemic across American society.

The reason American society is in danger is that decades of elite collusion, combined with the intentional use of cultural wedge issues as electoral levers, have left many Americans economically vulnerable and has misdirected their anger at minorities rather than at the people who have picked their pockets clean.

Vulnerable and angry people are prime targets for demagogues, and that's how the US wound up with Trump.

The evolution of American social divides into issues of morality (see eg: https://imgur.com/a2dTuWZ , or https://www.yahoo.com/huffpost/reaching-out-to-trump-voters-... ) in recent years has likely damaged American society irrecoverably. People who have diametrically opposed moral worldviews can't work together.