> It eliminates a huge swath of potential long-term contributors who know C well and don't want to change,

that pretty much described the current hurd dev community and its dying. I wouldn't advocate a full RIIR for most things but I think its a solid hail Mary to maybe make hurd relevant. The alternative is its going to be dead in a few years when the contributors all age out to spend time with their grandkids.

At this point... if you want to contribute to a UNIX-like microkernel-based OS written in Rust, Redox is right there

I'll believe it when Netcraft confirms it