I’ve known about this concept and Peter Turchin, Russian population ecologist turned global historian, for some time now. Turchin approaches history in a uniquely quantitative manner which has drawn the attention of many a blogosphere intellectual, and very recently on Ribbonfarm.
The concept of ‘elites’ and their ‘supply vs demand’ is one aspect of Turchin’s broader project of assigning discrete measurable attributes in order to model how political stability can emerge in complex societies. Turchin suggests that an indicator of imminent societal collapse is the increasing supply of elites (increased enrolment in higher education) relative to the number of positions in the ruling class (market-demand for white-collar ‘elite’ roles).