I don't think that's what Rob Pike was saying. It is more along the lines of, if you hire smart people who don't know C++ and then teach them C++, it is still a very long learning curve since the language has so many gotchas. (And you can make the same argument for Haskell.) You spend a lot of time on becoming a language expert rather than learning about the domain you're actually interested in.

It's better to have a language that can be picked up easily and that you can be competent in without needing to be an expert. And this is something Go is known for.

The example you gave seems reasonable for any Googler to understand (once the errors are fixed). The contracts proposal does make Go a bigger language, but it seems worth it.