There is a new and updated take on this topic by Autor, Goldin, amd Katz:
The race between education and technology provides a canonical framework that does an excellent job of explaining U.S. wage structure changes across the twentieth century. The framework involves secular increases in the demand for more-educated workers from skill-biased technological change, combined with variations in the supply of skills from changes in educational access. We expand the analysis backwards and forwards. The framework helps explain rising skill differentials in the nineteenth and twenty-first centuries, but needs to be augmented to illuminate the recent convexification of education returns and implied slowdown in the growth of the relative demand for college workers. Increased educational wage differentials explain 75 percent of the rise of U.S. wage inequality from 1980 to 2000 as compared to 38 percent for 2000 to 2017.
Note that for the most recent rise in inequality across 2000-2017, most of it has happened within educational groups. The less polite way of putting that — my words not those of the authors — is that the real marginal product of education is explaining less of the variation in earnings, or in other words the higher earners are drawing upon something they are not getting at school.
Students of the “education as signaling” debate also should note that, due to these results, now a) signaling is more relevant for your early wage offer, and b) signaling is less relevant for your eventual wage profile, which in fact is now more determined by your personal level of skill.