LLVM is not going to take PRs written in Rust to fix the Rust compiler backend, for example.
Neither are OpenJDK, .NET, V8, JSCore going to take such PRs.
By the way, LLVM and GCC would also not take PRs written in C.
As for PRs: well yeah of course, when in Rome...
Same applies to C++ with CUDA, SYSCL, HPC/HFT frameworks, LLVM/GCC, AI compilers,...
They don't look dead to me, even if we as industry could be much better by now.
LLVM is not going to take PRs written in Rust to fix the Rust compiler backend, for example.
Neither are OpenJDK, .NET, V8, JSCore going to take such PRs.
By the way, LLVM and GCC would also not take PRs written in C.