The first industrial revolution was entirely about replacing high-skilled manual laborers with relatively low-skilled factory workers. There's no inherent economic law requiring such a shift to be a net drain on employment - sometimes 100 people manning power looms can do something cheaper than 90 skilled weavers.
Sometimes not, though: the clothes end up just being cheaper as a result and net employment in the clothing industry drops, but if there's anything resembling competition in the market there'll be a drop in prices, and now everyone who was buying clothes will create a bit more aggregate demand for other things. That's the "work in other sectors of the economy" part that occasionally gets mentioned as a solution, and is in large part why we're at 95% employment despite 4 centuries of "job-killing" innovation.
>> There's no inherent economic law requiring such a shift to be a net drain on employment -
Yes, there is. I just presented it with the TCO thing. What has been happening so far is that the displaced workers were offered jobs somewhere else because there was another need they could fill. The net drain does happen. It happens within the set of people working at a company, and the industry. Only if there is unmet demand in the overall economy does it not affect unemployment by having people do something else entirely - and I don't mean maintaining the machines, I already showed that to require fewer people.
>> sometimes 100 people manning power looms can do something cheaper than 90 skilled weavers.
The human labor per item still went down. You just threw a capacity expansion on top of the efficiency increase. That just means a competitor will be out of business soon meaning fewer people employed, not more.
It's full of product (all same model). Decades ago, prior to automation it was full of employee vehicles, and so was the overflow lot across the street to the west. The neighborhoods around there were thriving and now are quire run down.
We've been lucky in finding new things for people to do outside of industries where this happens. People can only consume so much in a day though, and as the labor hours required to fill human-need-hours goes down there will be a problem.
It's not necessarily the case that cost-lowering innovations will drive demand for labor down, even without increases in capacity. Usability innovations are often of this variety.
If I can hire two people who work half as fast but at 1/4 the price each because they require no special skills, I can profitably produce the same goods with half the input costs and a net doubling of the employment I create.
Such innovations certainly exist, and there are even some reasons to expect they'll be more common in the future: an uneven distribution of income means more places to find cheaper labor.
Sometimes not, though: the clothes end up just being cheaper as a result and net employment in the clothing industry drops, but if there's anything resembling competition in the market there'll be a drop in prices, and now everyone who was buying clothes will create a bit more aggregate demand for other things. That's the "work in other sectors of the economy" part that occasionally gets mentioned as a solution, and is in large part why we're at 95% employment despite 4 centuries of "job-killing" innovation.