[halomru]

But if a pipe-bending machine has a total cost of ownership of $100 per operating hour, your four pipe bending guys have a job as long as employing them costs less than $25/h. Where before they might be able get a higher wage, their wage is now capped and the cap is decreasing over time.

Of course there's other reasons to employ people (parent mentioned spending power, I would add political influence to the list). But the labor part of the employment decreases in value.

[vlehto]

If labor part decreases in absolute value, then the bikes too get cheaper in healthy competition. So the net effect is just inflation.

Historically the period from inventing the assembly line to the large scale deployment of factory floor robots is roughly from 1920 to 1990. The same time period saw the highest wages/GDP ratio in US than ever before or ever since.