“Achilles’ heel” indeed. That’s the experience with modern Fortran in many domains.
As I commented here, with just a handful of new facilities added to the language, Fortran can greatly overcome being an awkward language for many tasks i.e., anything besides hard-core number-crunching where, at times with some effort, many other programming paradigms and languages are able to do just as well as Fortran, or even better.
Too bad it’s proving impossible to get such few, new features introduced, again and again the practitioners feel the need but they are being ignored.
The world of Fortran is no longer that of Backus et al. Backus and co. set out do something that can possibly delight the practitioners, not merely meet some basic needs with a higher level language beyond Assembly. Now, with modern Fortran language development, it is perennially trying to do the barest of minimum to stay relevant and/or to manage the decline of Fortran. “Too little, too slow” is how it goes. The “voice of the customer” is being largely ignored.