From the article:
“The fundamental problems, he says, are a dark triad of social maladies: a bloated elite class, with too few elite jobs to go around; declining living standards among the general population; and a government that can’t cover its financial positions. His models, which track these factors in other societies across history, are too complicated to explain in a nontechnical publication. But they’ve succeeded in impressing writers for nontechnical publications, and have won him comparisons to other authors of “megahistories,” such as Jared Diamond and Yuval Noah Harari.”
“We are almost guaranteed” five hellish years, Turchin predicts, and likely a decade or more.
It is a fascinating article. See also this blog post.