The US is one of, if not the most, socially mobile countries in the west. Countries like the Nordics have much more equality of outcome, but the chances someone leaves the economic quintile they are born into is lower.
Paging through the Brookings document, it tracks pretty closely with what I have seen before. I dont see anything that contradicts what I have said (mobility is higher in the US than elsewhere).
1) Do you have a comparison with European countries that makes you think the US is worse?
2) What do you think US mobility numbers should look like? Pure randomness is not desirable either.
https://www.lisc.org/our-resources/resource/opportunity-atla...
https://www.brookings.edu/wp-content/uploads/2022/06/2022_FM...