And that might work if there is a linear relationship between apparently unnecessary engineering work and deaths. My argument is that such a relationship does not exist, or is not something we can model.

As this is HN I assume you have some understanding of software/IT etc. Do you think a project manager on a massive software project could do the same with security flaws? Reduce the engineering effort by some percentage and get a predictable increase in security issues? And lets say that this project has massive amounts of sunk costs, is hugely important for the livelihood of everyone involved and also classified and closed source. All you have to do to reduce costs is increase data breaches from one to three per year. Easy. But in a complex human-technical system leadership do not have that kind of control authority.