In Java world package managers and package registries work with prebuilt libraries because for JVM bytecode it's sufficient. And if they have native dependencies then they include compiled .dll or .so files that are built on developer's machine. This makes things simpler but has its own drawbacks (these dependencies work only on architectures and OSes developer thought of, there is no guarantee that the library will be compatible with user's environment, etc).

In Rust world everything is built from source, including native dependencies. Thsi makes build process much more complicated and necessitates running code on user's (developer consumes the library as dependency, not end user) machine to build everything that's not Rust.