Yes it does, alongside C++, Rust isn't available everywhere.

There are industry standards based in C, or C++, and I doubt they will be adopting Rust any time soon.

POSIX (which does require a C compiler for certification), OpenGL, OpenCL, SYSCL, Aparavi, Vulkan, DirectX, LibGNM(X), NVN, CUDA, LLVM, GCC, Unreal, Godot, Unity,...

Then plenty of OSes like the Apple ecosystem, among many other RTOS and commercial endevours for embedded.

Also the official Rust compiler isn't fully bootstraped yet, thus it depends on C++ tooling for its very existence.

Which is why efforts to make C and C++ safer are also much welcomed, plenty of code out there is never going to be RIR, and there are domains where Rust will be a runner up for several decades.

I agree with you for the most part, but it's worth noting that those standards can expose a C API/ABI while being primarily implemented in and/or used by non-C languages. I think we're a long way away from that, but there's no inherent reason why C would be a going concern for these in the Glorious RIIR Future:tm:.