I think it’s just poorly worded; it’s about the upward mobility of the _generation born after the Second World War_. This generation lacked opportunities and this created unrest in the 60s and 70s.
The previous generation – the one that reached adulthood before and during WW 2 – had upward mobility in the 40s, 50s, and wanted its children to have too
I can: https://en.wikipedia.org/wiki/C%C3%A9dric_Villani
( and of course Wikipedia has a list :) https://en.wikipedia.org/wiki/List_of_mathematician-politici... )