“ The left did this to itself. At some point in the last half century, it stopped speaking to people it didn’t consider politically acceptable. By dismissing the white working class as bigoted, it justified making no attempts to reach out to them or to undermine classist systems of oppression.” Bingo! You nailed it.
The other thing you need to know is that the Left created the dystopian society you describe by rejecting Capitalism, the only known system for creating new wealth. The other two, Feudalism and Socialism just redistribute a static, or shrinking cake of wealth. You have elected governments that took bribes from corporations, allowed them to hollow out the middle classes, abandoned the working class and sold out working Americans by allowing offshoring of their occupations.
Let’s hope Trump can reverse some of the “progress” of the Bush-Clinton-Bush-Obama decades.