Doesn't apply here, Go is largely as flexible, generic and versatile as C, minus a few restrictions and plus a few (awesome) additions. And the CGO interface lets you bind C libs as needed.

I write OpenGL apps in Go. Surely this is in no way characteristic of Google's internal use-cases.

Today's machines are multi-core and are not as bare-bones as to require manually carefully coded malloc/free calls. That's what's changed since C and that's what Go is (very well) designed for. Then a few syntactic goodies that don't imply performance side-effects or any black magic but that C didn't have: duck typing, struct composition, interfaces, all that.