The lack of diversity I am talking about does not come from averaging a large number, but from the fact that unlike Mississippi, all of Japan, Canada and the EU have very high standards of living, nationalized health care, and very extensive social safety nets, as well as very high education levels.

Simply put you and I have different definitions of culture.

To me GDP, GNP, level of education, standard of living, etc, are all economic measures, which are indeed numerical and thus trivially easy to compare.

But my definition of culture includes, language, national identity, customs (this is very different from laws), holidays, music, rituals, food, etc.

And I would argue that those things don't change even as GDP and standard of living go through revolutionary levels of change.

Prime example: Ireland.

For a very long time Ireland was one of the poor, agricultural nations of Europe. Then legal and tax changes were introduced and a few years later people were talking about the Celtic tiger, and English laborers were going to work in Ireland for the first time ever. And even now after the real estate bubble has burst, modern Ireland is astronomically far away from potato famine Ireland in terms of GDP and standard of living.

But culturally it is mostly still the same.

China before communism, China after the economic reforms in the 1970s, China today, all economically VERY differently. Culturally there's been big changes too, but not nearly as huge as the economic ones.

Right before Thatcher, Britain's economy was so bad, predictions had it reaching Albanian levels of prosperity in a decade or two. How culturally different is Britannia of that time compared to Tony Blair's cool Britannia of the booming 90s?

So Massachusetts and Mississippi are very different in terms of GDP, education and median income. But to me they are both obviously American. That's very different from Holland and France, or the UK and Holland, or France and Spain. While the GDP there is much closer, they are very, very different cultures.

Let's do a thought experiment:

You go to Holland and try to grok how to live there. You have an iPhone translation app that can translate text you take pictures of and voices it hears. You use that to make your way, pick up some Dutch and figure out things like how to buy food, how to get a job, etc.

Once you feel you get it, move to France and repeat. Then move to Spain or Germany, or Italy and repeat.

At the same time lets find someone form Holland who does not speak English.... crap that's not really possible. Germany maybe, if we look hard enough and go for the older population I bet we can find a German who does not speak English.

And we give them the same iPhone app and send them to a state in the US, and when they feel they grok it, we move them to another state.

Assuming you both happen to be equally bright and grok your first state in the same amount of time, who do you think will to through 5 states first? You in Europe, or the German in the states?

I'd argue that if you grok one US state, that's it, game over, you grok ALL of the US. English is spoken. Turkey day is Turkey day, as is July 4th. Food differences are slight, but the stores all sell overwhelmingly the same things. Except for a bit of local programming, same TV and music on the air, etc.