Yes, other countries have ethnically hybridized identities; Canada and Australia readily come to…
Lyman Stone

You may be falling for a little trick of parochial egocentrism, here. Having lived in all of the abovementioned countries, I have to say that whereas ‘British’ is ambiguously inclusive of ‘anyone who has a right to stay’ — but is disputed by ‘anyone who’s a bit xenophobic’ — this predates the existence of Kentucky etc by at least a couple of hundred years.

‘Turkish’ applies simply to ‘anyone who is in Turkey and wishes to consider himself ‘a Turk’’, rather than an ethnicity, per se.

When I first travelled in the USA I noticed that, in smaller towns at least, people often ask ‘What’s your name/Where you from/Why are you here?’

Brits of course say little — raise an eyebrow or perhaps a pinky over a porcelain saucer.

Turks almost always ask ‘How are you, what’s your name’ followed by ‘What do you think of Turkey?’

And I kinda like this. :-)

A post-national, unconditionally inclusive ‘post-ethnicity’.