"What has gotten materially better in America in, say, the last twenty years?" So! Much!
Survey data suggest that 59.2 percent of Americans are "thriving"—the highest percentage recorded in Gallup's 13 years of measurement. Take that, 2020.
Amidst the anger and nastiness, there are real signs that America is thriving.
Too many of your friends and neighbors are tribal idiots, but they're not the worst tribal idiots in recent memory, by any means.
Pestilence, war, famine, and death are all on the decline.