It's a stupid statement internally as well. Unless you can freeze time itself, deploying new versions of stuff isn't instantaneous. And what happens if you need to do a rollback of a component?
You revert the offending commit. That triggers an automatic deploy (or, even more likely, your buggy change gets caught in the canary stage and automatically reverted for you).
The Google philosophy is called "live at head" and it has a bunch of advantages, provided your engineers are disciplined enough to follow through.
Protobuf is built specifically for Google and Google's way of doing things. Not everyone is built like Google.
Yes, Google's internal infrastructure is that good. It's easy to get caught up in the "haha cancel products" meme and forget that this company does some serious engineering.