Earlier quoted context omitted.
Neither of the things you've listed sounds like diversity, it sounds like inequality. Why is half the country without proper education while the other ones are in the best research institutions in the world? And what does the people are those institutions spend their time on, if it's not helping the other half reaching the same position as themselves? The social experiment seems to be about how extreme you can really…
Inequality does create diversity as it gives people a vastly different life experiences.
One of the things we can be actually proud here in Europe (mainly western part though), a rather strong middle class and tons of help to the poor (maybe too much according to some).
I know its nice to find cheap poor folks desperate to work for peanuts, and you can pat yourself in the back how the environment gives everybody a chance to thrive, but that's not an American reality, just a self-perpetuating pipe dream.
US is great for the ultra-rich, good for the rich, not-so-good for middle class and outright shit for the poor. But good luck trying to get this accepted in the US where folks are spoon-fed from the childhood how US is best in everything, rather than some healthy amount of critical thinking.
Generally everybody, but in my humble experience Americans (and French) especially, profit greatly when (have been) living abroad for some time. Then we can have actual conversations what is great here and there and what outright sucks.