This kind of seems like it's focusing too much on my exact word choice and less the actual intent of my question behind it. The question I have is why following established principles should matter; I don't think it should be particularly surprising that someone might assume that making a language more usable for humans would be related to the number of humans who end up deciding to use it, and if that's not the case, I wanted to understand why my intuition is wrong.

> there are still industries where it is important to reduce the human tendency to make mistakes by taking appropriate measures. Ada was created for such an industry from the very beginning

This is a good point that I hadn't considered; it definitely makes sense to me that some domains might be less tolerant to human errors than others, and those domains would better reflect how well-designed a language is for humans.

> The "level of suffering" experienced by most people is probably simply not great enough to systematically take such aspects into account. But there are still industries where it is important to reduce the human tendency to make mistakes by taking appropriate measures.

Reading this part a couple of times, I think this might be where the nuance lies. My colloquial understanding of what it means for something to be ergonomic (and even by the idea of what"level of suffering" would mean) isn't quite the same as the measurement of how likely it is for something to induce human error. This might just be a case where the common use of the term isn't the same as how it's used inside the field of study, but I would have expected that the ergonomics of a language and measurement of the "level of suffering" would be with respect to the programmer, not the one experiencing the use of the software that's developed as a result. That isn't to say I disagree with the idea that the end-user experience should ultimately be more important, but I think that might account for the disconnect between what you're describing here and what I would have expected from a discussion around "programming language ergonomics" (which also might explain the difference between Ada and the other languages mentioned in this thread).