It's not meant to be an extrapolation; it's meant to be a comparison. The point is they did it more cheaply than is conceivable today.

No, it's specifically meant to illustrate that the inflation in infrastructure costs has been wildly faster than the inflation in the rest of the economy. The US can't build infrastructure for any kind of reasonable cost anymore and it is a big fucking problem.

It IS a big problem, but shifting stuff around in a dense city is different from piling some dirt into a shape on the tundra.

Most of the route is through extremely rugged mountainous terrain, not tundra, and developing a roadbed that can survive -70 F winters is a lot more involved than "piling dirt into a shape"

I traveled it before was paved, and it was, and is, a true engineering marvel.

Yes, I both unravelled my vast illiteracy on road engineering in general and understated a bit on purpose. My point was that there is not much existing infrastructure to take into account up there. Your point taken though.

And yet the infrastructure cost of rural areas is regularly cited as a problem, and moving people into big dense cities is proposed as the solution.

One meter of road in the middle of san francisco would be used more than a meter of road in rural areas.

While the costs are higher- so are the benefits

The benefits per dollar or per meter? How many passengers are traveling on a bus on Van Ness in a given rush hour?

I think you could argue that infrastructure quality has grown at a pace that justifies the increased expense.

Do you have examples? I feel like things have gotten 10x more expensive and they're built with half the quality. In San Francisco we have a leaning skyscraper, the Bay Bridge which some people are still unsure is safe despite being several years late and costing 5x as much as predicted, and the Transit Center which was however many months/years late and is continuously shut down for safety reasons.

I realize San Francisco is a microcosm, but in my experience the focus has been on extracting money via corruption and building the bare minimum you can without getting sued.

You could argue the money is going towards greater safety for workers, but I see no plausible argument that it's resulting in higher quality work.

The opposite. Modern infrastructure is shit compared to decades ago...

The point is that it cannot be.

According to the article it cost $4600 a day to build.

On a 8 hour work day on federal minimum wage that's only 52 workers being able to work on the entire project ignoring all machine and material costs.

Too right it couldn't be done today. Or there were a lot of costs accumulated by the project that were not assigned to the project.

I hope usd 4600 does not include labor costs of 10000 soldiers (salary, food, accommodation, etc.)

Classic government accounting problem. People look free to managers, so more stuff gets brought in-house than it should.

Oh balls, just realised I misread the comment about cost per meter as cost per mile so my calc is hilariously wrong!

Still the reported cost of the road at the tune excludes machinery and labour costs, it was purely material costs.