> I don't know what social mobility is.
You'll find in the article I provided that it offers the following definition:
Social mobility refers to the movement of individuals either up or down the socioeconomic ladder relative to their current standing, such as a low-income family moving up to become a part of the middle class.
Countries with high levels of social mobility exhibit lower levels of income inequality and provide more equally shared opportunities for its citizens across each of the five pillars.
This is, of course, precisely what we're discussing here.
For example, regarding Denmark, it notes:
Denmark holds the title for the most socially mobile country in the world, boasting an index score of 85.2. If a person is born into a low-income family in Denmark, the WEF estimates it would take two generations to reach a median income. In contrast, someone in Brazil or South Africa would take nine generations at the current pace of growth.
> And in that respect, citizens of the US are far better than the rest of the world.
The opinion piece you've cited makes absolutely no claims about how the US compares to other nations, and therefore does not support your claims.
It's of course a fascinating analysis. But it does not even broach the question of whether "citizens of the US are far better" off than those in other countries.