(and to the European countries too for that matter) who value education tend to move up quickly in western countries because the educational opportunities are there if you take them and the barriers to movement permeable. Asian americans are examples of immigrant groups that have done very well quickly. My guess is that poor americans who come from family backgrounds that do not value education much get stuck and that continues across the generations. But that isn't necessarily because the opportunity isn't there.

I also think the european countries you are looking at do a much better job in the educational system/apprenticeship programs of steering students who are not as interested in education towards viable careers earlier.