Go folks seem pretty persistent in espousing this belief, but I've yet to see many examples of it in action.
Most of the fields where rust is making headway, it is making headway for precisely the things that Go is not known for - lack of a garbage collector, strict and expressive type system, robust generics, etc.
Hmm not really, Go is close to Python / Java / C# / C++, not much for PHP / Ruby, people didn't build backend services outside of the web in those languages.
Imagine one second Kubernetes, Docker or Prometheus those app have nothing to do with PHP / Ruby. It's related to C++ / Java.
Prometheus is the equivalent of what's at Google and it was built in C++. Same for all the DBs outhere in Go: CockroachDB, NATS, etcd ect ... those are C++ applications related.
By far the most usage of Go is web backends. But it is true I should have mentioned Java in the language list. Go is a popular Java replacement.
However you are talking about projects that are not particularly language dependent as long as the runtime is reasonably performant. They could just as well have been implemented in Java. For many Rust would arguably be a better choice but that is not relevant. Go shines here, but Rust is barely emerging in these areas.
Rust is a C++ competitor in areas where C++ has no competition because a GC is a no go. This is also where the most prominent use cases are.
Most of the fields where rust is making headway, it is making headway for precisely the things that Go is not known for - lack of a garbage collector, strict and expressive type system, robust generics, etc.