It's a 3 person side-project over 3 months. I suppose he means that Rust is to thank for this level of polish and reuse of 3rd party libraries. My experience with Rust is similar and there are many projects I would consider impossible (practically not technically) without Rust.
Programs like shells or servers are expected to perform well and usually cannot afford the GC tax (more memory usage and pauses). I wouldn't use a shell written in a GCed language. That would leave them with non-GC'ed languages. C or C++ simply don't have a usable equivalent of Cargo/crates.io which makes 3rd party reuse slower, and then they have much weaker execution safety guarantees.
Programs like shells or servers are expected to perform well and usually cannot afford the GC tax (more memory usage and pauses). I wouldn't use a shell written in a GCed language. That would leave them with non-GC'ed languages. C or C++ simply don't have a usable equivalent of Cargo/crates.io which makes 3rd party reuse slower, and then they have much weaker execution safety guarantees.