It's absolutely not true, it's one of the lies being told by Rust 4 Linux people. The end goal is absolutely to replace every last line of C code with Rust, and that's what they will openly tell you if you speak to them behind closed doors. That's why there is always an implicit threat directed at the C maintainers about job loss or "being on the right side of history". The Rust 4 Linux people are absolutely attempting a hostile takeover and nobody should believe a word that comes out of their mouths in public mailing lists when they are contradicting it so consistently behind closed doors.