https://wtfhappenedin1971.com/
Certainly the fall of the Breton Woods monetary system was part of it.
Post-war, we embarked on a number of massive and economically-inefficient expeditions, driven largely by xenophobia and racism, which inflated the labor and time costs of American life across the board, both in the short and long terms, and made monetary inflation a necessity in order to forestall an economic collapse. The most prominent of these are the creation and expansion of suburban America and the car and consumer cultures required to make it possible, and the expansion of the military-industrial complex in the midst of the Cold War.
An America that had spent the 40s, 50s, and 60s continuing to build densely (reaping the benefits of efficient servicing of public needs), and focusing industry on export-ready products and services (preempting trade imbalances), would not have incurred the ever-rising costs of creating and maintaining sprawl, and would have benefited from pro-trade spending that actually delivered a return rather than falling into a black hole.
If I might be slightly hyperbolic: American hubris and intolerance blew up the American experiment about 80 years ago. It's just been exploding very, very slowly.
When I think of the current social and political trends, I'm reminded of Asimov's quote about anti-intellectualism in 1980. Or Douglas Hofstadter's Pulitzer-prize winning book, "Anti-Intellectualism in American Life", published in *1963*.
These things aren't new. They just wax and wane in power, over time, and recombine in new and interesting ways to yield long-term trends.