Rust has safety and zero-cost abstractions at it's core, they provide a by now quite stable interface. You can't just move fast and break things. You need to stabilize at some point or it's impossible to use it in real world projects that are also commitments of a certain kind. And for that stability you need some kind of consensus of what to work on and what not to do.

I think the primary value of these new toy languages is they can explore aspects freely that can't just be explored in a more mature language. Sometimes after a concept has proven useful a mature language might be willing to incorporate it.

But I wouldn't use them on a serious project, because there will probably be few libraries and maybe no long term support for it.