I'm sure that number would drop quite a lot if you decouple MAU that are only using Messenger. I'd go as far as to say that there's a reason that it's still not

I'm sure that number would drop quite a lot if you decouple MAU that are only using Messenger. I'd go as far as to say that there's a reason that it's still not completely separated from "Facebook proper" after a decade or so since Messenger became a separate app.