In my effort to try to use Python instead in my field, I fell down countless rabbit holes along the way (like being for a year or so one of the core contributors to Cython, in an effort to make "a better Fortran").
In the end though -- I decided it was time to just Get It Done, and just did what my supervisor had patiently and subtly hinted for years. Enough rabbit holes, just get it done in Fortran, and hand in the thesis...
I think what I learned most about (having an interest in compilers and programming languages) is the ignorance the rest of the programming language community, and computer science, has about the kind of things you are actually interested in when doing HPC. What kind of language features you care about and what idioms make sense.
Learning Fortran is super simple.. that is perhaps part of the problem that also people who are barely programmers can write (bad) programs in it. So what this must mean is simply a lack of programmers, full stop, being attracted to the field.
And...C++ is truly the most wrong language for this space there could be.