If the examples in the article aren't convincing, there are plenty of other ones. Eg., construction involves lots of manual labor, and lots of machines that are designed only for human operators. If automation reduces the demand for low-skill labor in other fields, the result should be a construction boom, as that sector reduces costs and snaps up more workers. But that's not what we see. In fact, in many ways it's the opposite - in NYC, subways now cost ~30x as much per track-mile (inflation-adjusted) as in the 1920s.
Unemployment in other sectors "should" result in a subway construction boom/plummeting costs only if low-skill labor were the largest cost component of subway construction in the recent past. Was it? I tried searching for a few minutes on Google Scholar to find the share of subway project costs going to labor but didn't turn up anything; maybe you can find something.
I did find articles that say labor costs have increased over time, but none that were quantitative about it. Without quantification it's not helpful.
Now extend that thinking. What if low-skill labour isn't the largest cost component in anything much worthwhile that we're not already doing? How would that affect the reasoning in this FAQ?
The extra cost of modern construction projects can easily be attributed to the increased compliance costs. Any building work that impacts the flow of traffic now requires full time traffic control (manual); Safety inspectors are now full time; Continuous testing and inspection of building materials and practices requires trained inspectors.
We have vastly reduced the injury and death rates associated with construction at the expense of increased number of people involved in assuring that safety and building practices are complied with.
