I don't see your point? Nodejs is installed in a custom directory and not added to PATH. It is used by Zed for providing npm support for extensions, and other things. I'm not a Zed developer so I don't know exactly.
It doesn't prevent you from using deno or bun in any way.
To quote you: "they don't want to rewrite everything" ...
Writing Rust often implies major refactoring and it takes so much time to write that your requests go: "pewf" closed due to the amount of effort it takes.
Anyway, been there, done that! Zig is probably the real future; it's a joy to write, it compiles fast, clear to read, and safe.
It has shared libraries and a proper integration with existing C/CPP code base.
You should try it, that's an amazing language with a real potential to replace the legacy.
I use rust only if we need performance, for small services. The industry does the same. People use node for backend but e.g. redis is in rust.
It's a good tool if you use it for the right stuff.
EDIT: redis is not in rust, but e.g. aws writes many services in rust