My parents are Irish. They went to England in the 70s during the troubles and came to the United States in the 80s.

I've had this conversation with them a few times. Obviously in Northern Ireland they were very "Irish." It was almost a given that they would be very proud of their culture and live within it. It was suppressed when they were kids so they were ultra "Irish" to make up for lost time. When they moved to England they were outsiders (kind of) since they were just a couple paddies off the boat. So they ingratiated themselves with the large Irish community in North London.

Since they moved to the United States most outward aspects of Irish culture have vanished. They are pretty much American at this point. They have mostly American friends, attend an American church, watch American football, eat American food, etc. In the United States it's relatively easy to assimilate and be "American" which is definitely one of the strengths of this country. There is no real sanction against maintaining one's culture however so people don't always feel a NEED to do so. They easily adopt American culture as it's pretty welcoming. The distance between Italy and the United States, the slowing down of Italian migration, and Italian success in the United States all contribute to less Italian culture among Italian Americans.