I suspect in part it's a combination of 1) Go is good enough as is (and some people don't mind Go's simple type system or the boilerplate-y but explicit error h

I suspect in part it's a combination of 1) Go is good enough as is (and some people don't mind Go's simple type system or the boilerplate-y but explicit error handling), and 2) the Go tooling is really good -- "go build", "go test", etc, would all have to be wrapped or rewritten with slower, buggier versions.