This is at its core a problem of elasticity of demand. Most factories are only tooled to produce a certain output, and business inputs are constrained more by their contract terms and raw material prices than they are by labor bottlenecks. As a result, the company is effectively moving from one bottleneck (labor) to another (resource constraints or market demand).

Compare this to labor-intensive industries like law software engineering. Increasing the marginal productivity of labor while there is sufficient demand for increased output generates that required output, until it reaches its new equilibrium. In these cases where there is substantially more work to be done than there is time to do it, and there's sufficient market demand to handle additional output (thinking especially with software engineering), then increases to productivity will generate increased demand without appreciably changing per-hour market-clearing wages.