Good thing he's saying it out loud, but for those who think actions speak louder than words, it was clear enough when he decided to buy Oculus VR for $2bn.
It makes sense after all: 75% of Facebook's money comes from a platform (smartphones) that was nonexistent 10 years ago. In 10 years it is possible that VR will represent 75% or more of the revenues of Facebook — they'd be fools not to invest in it early.