Poking an old thread here ...
I'm finding this interesting. I'm another hundred-percenter, here. I know a lot of people aren't nowdays, but when I was growing up, many were. Even my brothers have married Italian and half-Italian women, and I've found all of two non-Italian names in my family tree, neither on a direct line to me. Three of my grandparents were born in Abruzzi, and the other's parents were both born in Basilicata.
I consider myself more connected to Abruzzi, mostly because my mom told lots more stories about her Italian-speaking parents and grandparents. My dad's family connection was broken or more tenuous since his father was born here, and his mother was orphaned in the US at a very young age and raised in a rather unpleasant convent. So most of the stories I heard were about Atessa and Nereto in Abruzzi, and until very recently I didn't even know where in Basilicata my last name was from.
Mixes seem to be the order of the day nowdays. Initially, Italians only married those from their town, then province. Then, they had to at least marry another Catholic. And now, it's pretty much anyone marrying anyone. Although my oldest brother remembers one time having my dad make a remark to him when he was a teenager, "I want you to marry an Italian girl."
So at least a little of it was still there in my generation (I'm 48).