When I talked to some Googlers, they said me that majority of Google code uses Java and C++, not Go. That was few years ago, may be now that changed, but it seems to me that Java and C++ really runs everything everywhere.

Nobody sensible is going to rewrite everything in Rust all at once. They'll start with new tools or things they needed to refactor anyway. Then use it where it's appropriate (it's certainly not a universally applicable language, the tradeoffs Rust makes are well known). Maybe someday AWS will have replaced all their Java with Rust, but I suspect some bits will stay Java for quite a long time, or migrate to Kotlin or some other garbage-collected language.