IMHO, technological advances begets social upheaval and accelerating inequity are the root causes for the popular usual suspects (broadcast media, cars and suburbia, social media).
Orthogonally, since Trumpism, I've been more open minded towards explanations rooted in reactionary populism (revanchism) and white racial animus.
Bowling Alone is a popular book about the decline of "social capital" (community), which is a fair intro to the topic.
https://en.wikipedia.org/wiki/Bowling_Alone
IMHO, technological advances begets social upheaval and accelerating inequity are the root causes for the popular usual suspects (broadcast media, cars and suburbia, social media).
Orthogonally, since Trumpism, I've been more open minded towards explanations rooted in reactionary populism (revanchism) and white racial animus.