None of the Google fresh hires I know personally are stupid. They are talented people who could be just as productive in a C++ or Java codebase. Maybe even better when you have features like Java's streams or C++ templates to throw at non-trivial problems. They might need more time, but it's something easily budgeted for. If new hires have to be productive from the first day, that's a problem the company has created and not the employee. If other languages have too many ways to do something, just enforce only using a few of them, teams have and continue to do that.
I use Golang in my current job. The library ecosystem seems fine. But even as a "new hire", the language frustrates me sometimes. Go's concurrency is "easy", but has a minefield of problems. Just off the top of my head, for-loop semantics [which to Golang's credit, is being fixed but it is absolutely a breaking change], just being able to copy a mutex by accident. These are bugs I've written and not had fun tracking down. In a year I'll have all these footguns memorized, but I could also have spent a year getting better at any other language. Even at my experience level, the Rust compiler gives me enough grief for me to know that when it's happy, whatever I've written will work. Nothing about Golang gives me that confidence.
