Some do. But introducing new language to a team is non-trivial. And maintaining a project in more than one language has its own challenges. Rewrites of course are risky and expensive. So, Rust tends to get introduced very incrementally, for smaller projects, or for green field dev. Look at all the drama in the Linux kernel.
If they’re seniors then why not slowly introduce Rust to their existing codebases?
Some do. But introducing new language to a team is non-trivial. And maintaining a project in more than one language has its own challenges. Rewrites of course are risky and expensive. So, Rust tends to get introduced very incrementally, for smaller projects, or for green field dev. Look at all the drama in the Linux kernel.