> Go is still young, with a long productive life ahead of it [...] compared to the number of people who will use Go during its lifetime, we are but a tiny fraction
An assumption lurking in the last paragraph. Remember JavaFX and Dart, both languages backed by large corps who then pulled their support. Go could be at the peak of its popularity, about to tank. We don't know.
I'm thinking of Turbo Pascal for DOS. It was very popular, and then it sank to obscurity almost overnight, basically because it didn't have any answer to "how do I write a Windows program in this?" Its niche had been eliminated.
I don't think Go will vanish unless "network servers that run in text mode on unix" somehow stop being a thing. There is no Google product whose change of strategy could strand Go (unlike the others you name). If somehow all computing moves to phones and tablets, it could be stranded, but I can't imagine that happening.
Go on Android http://talks.golang.org/2014/gothamgo-android.slide#1
Not supported by the Android team, so don't expect to see it here: