Err... as much I'd like to have a VR headset and use it, I simply can't.

I don't have time to immerse myself in the environment where I don't see the reality that surrounds me (as in, people which share my public transport, cars that stop at the traffic lights next to me, my kids running around me, people I work with, etc.). It's not that I need the reality, but I can't disconnect safely. Facebook is easy. Just reach the pocket, get the phone, a few swipes and you are using it. Be it in the office, around your kids, in the waiting room, ...

I don't see how VR can provide you a FB scale of users.