Why has Europe rejected it's indigenous European cultures and peoples?

There is nothing wrong with having your own culture and not feeling the need to cling to past cultures. I myself am an Italian American with much more emphasis on American than Italian, I have much more interest in American history than Italian history because it's the American side of me that I identify with most. It doesn't mean that i rejected any culture I simply ociate with one more than the other. I think this is true of most people.