> from what i can tell even the android binder rust rewrite is vestigial.

This is incorrect. The android binder rust rewrite is planned to wholly replace the current C implementation.

https://www.phoronix.com/news/Rust-Binder-For-Linux-6.18

And most of the big drivers written for Apple M-series hardware are written in Rust, those are not simple rewrites or proof of concepts.