Some other language need to step up and rewrite/replace LLVM then, because no language that relies on a ~30 million loc backend written in C++ can ever hope to replace it.

Zig plans to make LLVM optional. Rust has Cranelift. Go afaik has no dependencies on the C++ ecosystem including LLVM. Python and some other languages are built with C, not C++. So, progress is being made slowly to replace LLVM as the defacto optimizing code backend. Alternatives are out there, may they compete and win! C++ makes me pessimistic about the future of humanity..

Languages don't write code, people do. No one has rewritten LLVM because it already exists, and such a project would be insanely expensive for little benefit.