I'm not surprised by this.
The general attitude around R4L is that it's largely unneeded and for every 1 person actively working against the project, there are 10 saying either "waiting and seeing if it works is the right decision" or "if rust is so good they should prove it."
So as a R4L developer you're expected by the community to fight an uphill battle with basically no support on your side.
We will likely keep having developers on that project continue to burn out and leave until the entire thing collapses unless the decision is made ahead of time to cancel the project.
Every time I read any news about Rust for Linux I leave disappointed by the entire kernel community.