"8. Google does not use Angular in production for their flag apps like Gmail or Gplus."
Angular is newer than Closure, so this is to be expected. Google does however use Angular for certain newer web properties, e.g. the Google Developer Console (App Engine, Compute Engine etc.).
"9. Vendor lock. And because Google does not use Angular in production, they can kill Angular anytime. You know that Google is still kind of agile company, not having a problem to kill any project despite it’s used by milions people."
As mentioned in point 8 above, Google does use Angular, both in production and internally. Furthermore Angular is open source and has a thriving community - Google can’t "kill" it in the way it could end-of-life Google Reader. Rather, there is also a precedent for the opposite - GWT. Google turned ownership of GWT over to a steering committee and is still heavily invested and a a major contributor.