I think this is questionable logic, the last statement I mean. The Black Death killed nearly half the total population of Europe across all age groups (in some regions and whole cities, it even wiped out 70% or more of their inhabitants. That level of life destruction creates an immense, definitive shortage of labor for the urgent needs of a devastated society. The 1918 pandemic killed tens of millions, but proportionally, this was a comparatively miniscule fraction of the world population and of the working population in the industrialized world of 1919 onward. Certainly not enough to heavily affect labor supply or cause massive changes in how working populations relate to their employers