Seven to ten generations are required before the descendants of high and low status families achieve average status. Thus in modern Sweden the descendants of the eighteenth-century nobility are still heavily overrepresented -- 300 years later -- among higher social status groups: doctors, attorneys, the wealthy, members of the Swedish Royal Academies. In the United Kingdom, the descendants of families who sent a son to Oxford or Cambridge around 1800 are still four times as likely to attend these universities as the average person. Social mobility rates have also been relatively impervious to government policy. They are no higher in societies like Sweden, with generous interventions in favor of the children of disadvantaged families, than in the more laissez-faire United States. For that matter, they are no higher in modern Sweden than in eighteenth-century Sweden, or medieval England.
It reminds me of a friend, a scion of an old and wealthy family, whose self-description was "downwardly mobile".