And hiring right, or being prepared to train/let new hires climb up a steeper learning curve than hiring someone with Python experience for a Ruby app say.

Rust has reached that critical mass I think, got past the chicken/egg issue of experienced people to hire & companies interested in hiring them (to work on a rust codebase). Against the odds I think, there are plenty of languages you hear about similarly up and coming that haven't (D, Zig) or have only in a niche (F#, Swift, Kotlin - the last two I include mainly because I'm thinking Go could so easily have gone the same way, just been the one Google pushed for K8s plugins and GAE applications, not used generally as it is despite being a general-purpose language).