Go is quite similar to Limbo, by some of the same authors, how much success did it have outside AT&T?
No, it was adopted quickly because it's a simple, script-like language producing static binaries that didn't require any runtime, highly portable with built-in cross-compilation, requires very little resources, is able to perform pretty damn good and has an extensive standard library (although not perfect) supporting many modern technologies.
That are a lot of boxes it ticks off. I remember wanting to start hobby projects with friends where the end-result would preferably be a native binary, and the limit was that I was the only-one with a C/C++ background. Now anyone with some scripting background can pick up Go in a few days, without having to worry too much about a build system, portability, cpu architectures, performance, memory leaks, ...
Sure, Google was the initial push, but it only really took off once projects like Docker showed it's potential.