In a new paper in Psychological Science, Heiner Rindermann and James Thompson quantitatively model the wealth of nations based on a variety test scores, evidence of scientific and engineering skills, and Charles Murray's Human Accomplishment database of eminent individuals from Homer to John Von Neumann. Looks like La Griffe du Lion's smart fraction theory comes out looking good.
Cognitive Capitalism: The Effect of Cognitive Ability on Wealth, as Mediated Through Scientific Achievement and Economic Freedom
Heiner Rindermann and James Thompson Chemnitz University of Technology and University College London
Abstract Traditional economic theories stress the relevance of political, institutional, geographic, and historical factors for economic growth. In contrast, human-capital theories suggest that peoples' competences, mediated by technological progress, are the deciding factor in a nation's wealth. Using three large-scale assessments, we calculated cognitive-competence sums for the mean and for upper- and lower-level groups for 90 countries and compared the influence of each group's intellectual ability on gross domestic product. In our cross-national analyses, we applied different statistical methods (path analyses, bootstrapping) and measures developed by different research groups to various country samples and historical periods. Our results underscore the decisive relevance of cognitive ability-particularly of an intellectual class with high cognitive ability and accomplishments in science, technology, engineering, and math-for national wealth. Furthermore, this group's cognitive ability predicts the quality of economic and political institutions, which further determines the economic affluence of the nation. Cognitive resources enable the evolution of capitalism and the rise of wealth.
And here's a big graph from the paper (click on it to see the right edge): 
