Agreed. What I would really love to see is whether a "historical economist" (or whatever those are called) could estimate the statistical value of a human life as defined by people's own revealed preferences. This is the sort of calculation where we infer how much each of us values our own lives based on the amount we are willing to pay to avoid small chances of death. In the US today, the number is about $8 million now, and is surprisingly consistent (within a factor of 2) over many possible inference methods.

https://en.wikipedia.org/wiki/Value_of_life#Life_Value_in_th...

(Of course, there are exceptions where people effectively pay rates of many billion dollars per life to avoid emotionally salient risks, like terrorism.)

The OP article gives the misleading impression that society's changing values are mostly due to moral progress (presumably arising, I guess, from people being persuaded by moral arguments, or from certain societal norms taking hold). But it's almost certainly the case that you can explain the vast majority of the change by economic developments, especially following the dramatic rise in per capita wealth starting with the industrial revolution. The dark implication of this is that if per capita wealth falls drastically in the future, which is possible depending on technological developments, then we are likely to see a regression in moral attitudes.