You can make similar criticisms of much, perhaps most writing about supposedly world-changing technology. Issues like infrastructure and implementation costs are routinely glossed over or omitted entirely. The Hyperloop, however, is especially problematic both because of the exceptionally large role infrastructure plays in serious discussions of the proposal and because accepting Musk's cost estimates at face value requires pushing aside consensus opinion on some well established points.
Here's how I put it in an earlier comment thread.
It's useful to step back and think of this in terms of knowns, known unknowns and unknown unknowns. There are a lot of aspects of building an intercity vactrain that are so far outside of our range of experience that any cost estimate has to be highly speculative -- independent experts tend to think Musk is being highly optimistic in these parts of his proposal but they can't say conclusively that he's wrong – but when it comes to things like putting large structures up on pylons or down in tunnels, we have a lot of relevant experience.
Remember this one?
[Michael L. Anderson, an associate professor of agricultural and resource economics at the University of California, Berkeley.] said that while some of the infrastructure is novel, the elevated guideway was not unlike existing structures such as the Bay Area Rapid Transit's aerial tracks. For the Hyperloop's tracks, that alone would cost in the tens of billions. As for the pipeline for the cars, he said, oil pipelines are $5 million to $6 million per mile, and they are seven times narrower than the Hyperloop's would need to be. In addition, the Hyperloop track could not change direction abruptly the way an oil pipeline could.
"It really has to be built to much higher standards than anybody has ever built a pipeline to," Anderson said.
As a general rule, elevating structures greatly adds to the cost. Building something to exceptionally tight tolerances (such as those required to maintain a near vacuum over hundreds of miles of track) greatly adds to the cost. Doing something big for the first time usually has the same effect. The third is a known unknown. The first two are pretty much knowns. Engineers have been dealing with these questions for a long time.
Unlike pure science, I don't think it's possible to write about technology effectively without seriously addressing issues like cost and implementation and, in general, viability. Implicit in pretty much every story on new tech is the promise of impact in the near future, and if the tech isn't viable that promise is deeply misleading.