All cultures mimic, adopt and modify aspects of other cultures. See: New York pizza, Australian beer etc. It doesn't follow that the resulting outcome is any less a valid expression of national cultural identity.
Likewise, I don't follow the connection between having a national identity and having national borders.
I once invited my neighbour over for dinner. He introduced me to his BBQ recipe which I now make all the time for my family. But he also got drunk and pissed himself on my couch. I won't be inviting him to move in with us any time soon, despite us having some culinary cultural overlap.
All cultures mimic, adopt and modify aspects of other cultures. See: New York pizza, Australian beer etc. It doesn't follow that the resulting outcome is any less a valid expression of national cultural identity.
Likewise, I don't follow the connection between having a national identity and having national borders.
I once invited my neighbour over for dinner. He introduced me to his BBQ recipe which I now make all the time for my family. But he also got drunk and pissed himself on my couch. I won't be inviting him to move in with us any time soon, despite us having some culinary cultural overlap.