Obviously, there’s much at work, and it will require different disciplines to arrive at a holistic explanation and solution. But allow me to humbly take up one strand and suggest something that is never discussed, yet seems so self-evident.
At the turn of the last century, when Italian-Americans poured in large number through Ellis Island, they encountered what was then called—quaintly, and without irony or angst—an Americanization program. They were actually taught to love their new country.
One driver behind the assimilationist push was the fear that the Italians and other immigrants such as Slavs and Jews would bring in—and cling to—socialist and anarchist ideas ascendant in their native lands. By mid-century, the only traitors helping the Soviet cause were people with long American pedigrees like Alger Hiss.
The immigrants who experienced the Americanization program went on to become full-fledged members of the Greatest Generation. They endured the Depression, defeated Nazism and fascism in World War II, then Communism in the Cold War. To say the least, they met the existential questions of the day. No fewer than 14 Italian-Americans received the Congressional Medal of Honor for bravery in WWII.