> I must admit that I have a more pastoral and conflict-adverse personality, so the idea of New York as an ideal is difficult for me to comprehend.

I still don't get this. I don't think that NYC is a high-conflict place at all. I'm not sure I'd quite call it "pastoral," really, but the outer boroughs are much closer to medium-sized cities in the rest of the US than to Manhattan - houses with yards and garages, strip malls with large parking lots, etc. Sure, there are areas where you're surrounded by skyscrapers and enough bright lights to ensure the city never sleeps. But that's a pretty small part of the residential population of NYC.

Or in other words, I think you'd be perfectly happy living here, given the preferences you've expressed, as long as you didn't live in Manhattan (and not wanting to live in Manhattan far from unusual!). If you find that merely being in a subway car or in line at a store with someone of a different race/culture uncomfortable, maybe NYC isn't the place for you, but I have no reason to believe from your comments that you're that sort of person.

(And you might still prefer rural areas where there are acres of land between you and your closest neighbor - which is fine! I'm not saying that we should cover the world in New York Cities. I'm just saying that it's empirical evidence that multiculturalism is stable, and not just for people who voluntarily choose in adulthood to move to a dense cosmopolitan city.)

I think you're right that there is a lot more informal, self-directed ethnic/cultural affinity than I was selling. But none of that has any level of structure that gets anywhere close to ethno-nationalism, with independent political entities and representation and policy between the ethnic enclaves. There are things like Hatzolah, yes, but there is one NYPD for all neighborhoods. There's one housing policy (and one affordable housing lottery). There's one minimum wage. There's one policy on how much to cooperate with ICE. And so forth. And there's one set of elections for influencing those things. (I would actually argue that there isn't enough political autonomy for the boroughs, but for the reason that smaller political entities are less prone to corruption and more likely to give opportunities for meaningful representation, not because different boroughs have independent and distinct cultures that require different political goals. I don't think we should have, say, two different police departments in Crown Heights for the black and Jewish communities, but I do think the police department in Crown Heights should be a smaller entity - with a smaller budget and smaller political influence - than the NYPD as it is today, possibly a Brooklyn Police Department, possibly even smaller. So I'd agree with your point above regarding size/scale, but I don't think that division on cultural or ethnic grounds is required.)

I'd believe the argument that NYC doesn't offer evidence that people will voluntarily give up ethnic/cultural identities as a way of living day-to-day. But I think it does offer strong evidence that people with these separate identities can be happy, successful, and peaceful with a single government.