Though I haven't read Kurt Andersen's EVIL GENIUSES: The Unmaking of America: A Recent History, a review in the NY Times points to some important elements to look for in this account of what went wrong in America beginning in the 1970s.
What America lost, according to Andersen, is "an openness to the new" in favor of a "mass nostalgia." I experienced this in multiple ways--culturally in music and politically in the resistance to the new technologies needed to spare the world the ravages of climate change.
Andersen's book is described as "saxophonely written," and since I'm a sax player, I will point out that a look backward is not necessarily a bad thing, if the aim is wisdom rather than nostalgia. Both classical music and jazz spent most of the 20th century pushing forward into ever greater abstraction and complexity until the music became largely unlistenable. If the audience rejected the new music, the composers and performers would point out that past innovators like Stravinski or Charlie Parker had also experienced resistance to their innovations. Ultimately, this means of rationalizing increasingly abrasive music began to wear thin.
(click on "read more")