We have entire userspace network protocols, ePBF, and to some extent even ePool pooling ideas from microkernels. But A single disgruntled kernel dev is enough to stop Rust device drivers from existing, so no, the idea is still not here.

That didn’t happen.

Even the Asahi Linux lead threatening Linus with a witchhunt against all kernel maintainers did not manage to finish off the ongoing Rust integration. People may not like it but it isn't going down easily.