[dragonwriter]

> But it is well known that the so-called 'Protestant work ethic' is a strong component of white American subculture, whereas it exists less strongly in the black subculture.

To the extent that this popular belief reflects reality (which is much less, I think, than you imply), I suspect it is not so much a durable, independent artifact of different culture so much as a difference in experienced utility of work that is reinforced through continuous experience in each generation.