If rationality were a requirement for progress, progress wouldn't exist. The beautiful fact of evolutionary processes it's that rationality is not necessary. But I digress...

Needs change with time. In the current context, if Go is an improvement in some tech areas I think it will get some degree of success. Otherwise I think will decline after the first hype.

By the way, I agree with you about writing more code to overcome language limits. The hope here is that using idiomatic Go you will end up, no matter what, with a reasonably understandable code base, even for libraries and tools. It's a goal, I don't know if reachable or not.