Steve Klabnik and Sean Griffin were both early adopters of Rust (and are now fairly visible members of the community), and I believe that helped sow the seeds of the language in parts of the Ruby community [0].

I think Rust managed to also cultivate a community that was very much like Ruby’s [1], which brought people over.

[0] cf. Klabnik’s “Rust for Rubyists”

[1] mostly being very “people-oriented” in terms of inclusivity and documentation, as well as putting effort into ensuring that the language and its tooling provide a lot of “developer happiness”