Hiring Fortran programmers is risky because there's so few and those that claim to know it might either be exaggerating or simply not good at it. It's not just the language, anyone can learn the syntax. It's making sure that whoever you bring in can actually do the job
The "Hiring Fortran programmers is risky" argument is incorrect. This is, in fact, the whole point of Fortran, that anyone as dumb as a rock "would" (not "could" or "might") write performant code. There is currently no other language that can achieve this. Any other language claiming this capability is essentially recreating Fortran (perhaps with a slightly different syntax). Fortran Standard has been pursuing this sole goal for 70 years and has become extremely good at it.
Your argument applies very well to C++, though. But it's not too hard to catch a novice there, either.