“Early on, four schools of thought emerged as to why capitalist economies have these long waves. These schools of thought revolved around innovations, capital investment, war and capitalist crisis. According to the innovation theory, these waves arise from the bunching of basic innovations that launch technological revolutions that in turn create leading industrial or commercial sectors. Kondratiev’s ideas were taken up by Joseph Schumpeter in the 1930s. The theory hypothesized the existence of very long-run macroeconomic and price cycles, originally estimated to last 50-54 years.” ~Kondratiev Wave