It turns out the problems facing the coal industry are not of recent vintage:
The economics of coal posed a myriad of problems for the UMW. . . Even with prices falling the relatively high cost of coal led such major coal consumers as the railroads, the steel industry, and public utilities to introduce more efficient methods of fuel consumption. Efficiency in fuel consumption caused a long-term decline in the demand for soft coal that was aggravated further by the competition of oil and natural gas for the domestic heating and light industrial market. In August 1921, John L. Lewis would have to have been blind to miss seeing the economic disease that blighted bituminous: too many mines and too many miners producing too much coal.