Some services span many many hosts (not sure I can say how many though). Not because they are inefficient; that's because it takes many cpus to do to support our trips/eaters/etc.
Most of the services benefit from speed/efficiency of Go: the more effective the language (runtime) is, the less we pay for hosting it, the cheaper the service to the customers.
Given that, the GC costs are still significant. Depends what you compare against.