I've built several large-scale buildings and developments at urban scale in California and Nevada, both heavy heavy union states.

I can't point to the systemic problem leading to the delays but I can tell you that any job even tangentially related to construction requires high wage labor. This is universally true for civic projects.

Some of those unions (e.g. electrical workers, carpenters) provide exceptional training services for apprentices. Others (e.g. the people holding the stop signs at highway construction sites) are mostly strong-arm groups.

These groups could be causing delays and from personal experience I can tell you they do, sometimes. But overall I can certainly say that the point you made here is not the reason why projects are delayed.

It's all very well to pay someone well and expect good results for the money, but that person is still a member of society and will be affected by the things around them. I'd argue that someone who hears constant negativity in the media about how everyone is underpaid and living in poverty, and sees the person serving their coffee at a diner working their third job, and knows that their wife is working longer hours than they are for much less money, is going to be less productive as a result no matter how they're treated as an individual. Poverty is a structural problem in society. It doesn't just affect poor people.

Poverty may have been prevalent.

Maybe focus more on inequality and uneven reward? The Depression seems to have often been, as with the WWII recovery, something of a leveller.

https://en.m.wikipedia.org/wiki/Baumol's_cost_disease

This can’t be a complete explanation though as other places can still build things.

I'm totally nitpicking on your style here, but IMO this line reduces the value of the rest of your comment. Without it, your comment could be interpreted as a call to action, eg to encourage people to take more pride in their work. With it, it's clear that you've already given up, and you're not really adding anything except maybe encouraging others to give up on stuff too. That makes me sad.

This fully embodies the experience of the modern-day Agile experience in software development. "I know you're a senior but I (a non-technical Product Manager/Scrum Master) am going to have to check in multiple times a day and dictate every single feature and how it's built."