Isn't Rust still very seldomly used in the areas where CUDA shines (e.g. number crunching of any kind, let it be simulations or linear algebra)? Imo C++ or even Fortran are perfectly fine choices for those things, since the memory allocation pattern aren't that complicated.
Not only that. Fortran is very good for writing number-crunching code. Modern Fortran is a pretty ergonomic language, it gives you a really easy way to auto-parallelize things in many ways, and new Fortran code is being produce unironically. Of course it normally uses the treasure trove of existing numerical Fortran code. (Source: a friend who worked at CERN.)
