That would be an impossible expectation on the Go toolchain. The pull through proxy can’t magically avoid the need to transfer all dependencies to my device, especially including any native code or other resources. Large projects are going to need to download stuff - think about how some cloud clients build code dynamically from API definition or how many codecs wrap native code.
Similarly, newer versions of Go change the compiler–which to be first is a good thing–so even if I start with the same source in Git I might not have the same compiled bytes in the result.
Again, mone of this is a bad thing: it just means that I want to compile binaries and ship those so they don’t unexpectedly change in the future and my CI pipeline doesn’t need to have a full Go build stage when all I want is to use Crane to do something with a container.