Paradigm shifts in physics happen at 80-year intervals due to two constraints on physics and technology development that constrained the duration of paradigm development to average 80 years. These two constraints cause three generations to produce a physics paradigm and begin the industrialization during an industrial revolution. During each industrial revolution, there is a depressionary era due to the low productivity growth of the dying industries and the transition of the economy to new industries. Another depressionary era begins about 30 years after the end of the depressionary period of the industrial revolution. These depressions are times of high productivity growth when the industries reach the mature stage. The switch of emphasis from product innovation to process innovation causes depressionary eras during which the high corporate and consumer debt, product satiation, oligopoly formation, and increased automation that reduces the demand for labor causes depressions. The duration of the Kondratieff waves varies from about 40 to about 53 years depending on how quickly a paradigm is accepted.
The Paradigm Shift Cycle as the Cause of the Kondratieff Wave in Kondratieff Waves: Processes, Cycles, Triggers, and Technological Paradigms 2022, issue 6, pp. 39-63 (January 2023)