Keynesianism failed because it employed the Industrial Reserve Army and that is what resulted in inflation. In other words, capitalism requires the Progressive Production of a Relative surplus population or Industrial Reserve Army to prevent a wages breakout? This was finally resolved by offshoring and automating production as a means to discipline labour. Full employment gives workers confidence to demand fairer pay and conditions and this is in direct conflict with the profits of corporations, and causes crisis. Capitalism is a very frail system, always teetering on the brink of another crisis.
