One of Arthur C. Clark's famous laws was, "Any sufficiently advanced technology is indistinguishable from magic." I would revise that sentiment to be: "Any sufficiently advanced technology is indistinguishable from science fiction."
I grew up reading about virtual reality in William Gibson's Neuromancer and Neal Stephenson's Snow Crash. I played the early virtual reality game "Dactyl Nightmare," and even worked at Disney Imagineering as an intern when they developed a VR ride based on flying Aladdin's magic carpet. I imagine Mark Zuckerberg read the same books and had the same experience, perhaps excluding the magic carpet.