>By-the-by, isn't it the case that the major differentiation that has
>occurred in the US over the 1980s and 1990s is the massive opening
>up of the wage premium between college graduates and the rest?
That's one part of it, for sure. To lapse into jargon, if you sort the U.S. pop into demographic cells - by race, age, education, experience, occupation, etc. - not only has between-cell inequality increased, so has it within cells. Dispersion, as the economists prefer to say, is everywhere.
Doug