Source: Fig. A of Lawrence Mishel, The Wedges Between Productivity And Median Compensation Growth. (Spotted via emptywheel.)
Note that the data represents growth of real hourly compensation for production/nonsupervisory workers vs. productivity, 1948-2011. These workers represent more then 80% of the labor force; the productivity number is for the entire economy. I do not think anyone serious would argue that the lion’s share of productivity gains were achieved only by supervisory and highly-paid workers. If there has been such a revolution in CEO skills, it has certainly been well hidden. (Note that if much of the gain is due to capital, or changes in technology, there is no reason why it should not be shared any less equally among workers as it had in the past).