> But giant geographically, economically, ethnically diverse polities like the US have a much harder time.
I've heard this refrain from a number of otherwise sensible people and it always makes me shiver. Not only does it imagine all the world's non-US megacities are quaint "tightly-knit" monocultures, but the dog-whistle "ethnically diverse" component is particularly repellant. To give the benefit of the doubt: that's probably not intentional, but I really wish we could end this meme as to why the US has inadequate public services.
You've heard it from sensible people because there's a significant social-sciences literature studying the idea, and largely confirming it – no "dog-whistles" required. I want more ethnic diversity in the US, but my eyes are open that in practice, such diversity (for at least a generation or two, maybe longer) tends to weaken political support for public services, and strain such services' competent administration. The right cultural & policy innovations might be able to overcome this effect! But probably not, if merely acknowledging it becomes a taboo, and we pretend it's not an effect at all.
And it's not just ethnicity – it's many dimensions of "largeness" and "diversity", including geographic dispersion, variety of economic industries and incomes, religions, density, etc.
Only 2 countries in the world have a larger population than the USA: China and India. They're not known for top-notch free public services, either – though China's anti-union, anti-local-control authoritarianism allows public infrastructure development at a crazy pace, and (forced relocation into) public housing. The other 7 most-populous countries (Indonesia, Pakistan, Brazil, Nigeria, Bangladesh, Russia, Mexico) aren't stellar examples of public services, either.
The "high services" models most often highlighted tend to be less than 1/30th the population of the USA and far more culturally/economically homogenous (the Nordics), or at most 1/6th to 1/5th the population of the USA (UK, France, Germany), and still less varied geographically, economically, and culturally.
> but I really wish we could end this meme as to why the US has inadequate public services.
You're going to need more than wishing for this to go away, because as other commenters have pointed out, this isn't dog-whistling. It's empirical fact that a greater share of tribalism and sense of community (of which, surprise surprise, similar race/ethnicity is a factor) improves socialized goods/services.
Inconvenient facts are not racist when simply noted, and that's a meme I'd wish would go away.
I don't know if "ethnically diverse" affects public services here in the US, but we are more significantly more diverse than the majority of other first world countries.
I've heard this refrain from a number of otherwise sensible people and it always makes me shiver. Not only does it imagine all the world's non-US megacities are quaint "tightly-knit" monocultures, but the dog-whistle "ethnically diverse" component is particularly repellant. To give the benefit of the doubt: that's probably not intentional, but I really wish we could end this meme as to why the US has inadequate public services.