The fact that the author is a developer of Chapel pretty neatly explains why "no new language was adopted" is valued as failure, the article itself makes little effort to argue for that value judgment.
> I didn’t put Chapel on my list of broadly adopted HPC programming notations above, in large part to avoid being presumptuous. But it’s also because, regrettably, I don’t consider Chapel’s support within the community to be as solid as the others on my list
Author here: I didn't go into more detail on this than https://chapel-lang.org/blog/posts/30years/#maybe-hpc-doesnt... because I felt like the article was long enough already and that I'd recently covered that topic in detail in this series https://chapel-lang.org/blog/series/10-myths-about-scalable-... summarized here https://chapel-lang.org/blog/posts/10myths-part8/#summary