Isn't it heavily used in Google Cloud?

Last time I paid any attention to Google's high level conference presenters (like Titus Winters), they almost didn't use Go at all. Judging by the sibling comment, this hasn't changed much. For some reason people are thinking that half of Google is written in Go at this point, when in reality if you listen to what they themselves are saying, it's 99% C++ and Java, with a tiny bit of Python and other languages where it makes sense.

It's just a project from a few very talented people who happen to draw their salary from Google's coffers.

C++ and Java. Go is still used, but it's never caught up to the big two.