A lot of it is an artifact of America’s global hegemony, which we’ve squandered over the past decades.
And as we’ve imported the Third World, more and more parts of America become as the Third World.
So they essentially move to a place that’s just like home with a (likely) stronger currency and likely more pleasant weather.
Good for them. Not good for us.
I don’t disagree with the larger point, but the argument made about “every objective measure” is suspect, though admittedly depends on what the measure(s) is/are. We may “feel” this way, but that’s subjective, not objective.