[epage]

There is sccache (https://github.com/mozilla/sccache) so a first step would be looking to see why it isn't used more to see how to lower that barrier.

Another idea is crate-build caching so local and CI can pull down a pre-built dependency, rather than building locally. This would need to handle rust versions, feature flags, architectures, compiler settings, etc. This would most help CI since the result would get cached locally

The last idea I'm aware of in this area is watt (https://github.com/dtolnay/watt). If the design and implementation was finished to allow proc-macros (and maybe `build.rs` scripts) to opt-in to a sandboxed wasm environment, we could have a local and networked binary cache for these which would dramatically improve Rust build times (and security). Some people outright avoid proc-macros because of the build-time impact.