It is a technological leap perhaps bigger than the advent of color television and cinema. By having a separate image for each eye, we're simulating another facet of our vision as it appears to us, which would be depth perception. Is it perhaps this fundamental difference that you're missing?
Technically, Vectrex or Master System had googles that allow separate images for each eye.
I'd say that the main "new" things for customers is the fact that it's linked to head tracking (but the tech isn't actually new, at least in labs...)
But you're wrong if you think that depth perception is mostly stereoscopy. Stereoscopy is a part of depth perception, but it's only a *part* of it. The scale and the focus distance are two other key factors (and in fact, if scale and stereoscopy gives different clues to the brain, the brain usually opt for the scale... if you're showing a ball that gets closer (according to stereo vision) to a user wearing a headseat and whose size is decreasing, the user brain will usually decide that the ball is going away, and not closer).
Fortunately, scale is a part of VR, but the focus distance is always at infinity in a headset (at least for now, but that's probably for a lot of time), and that's most probably one of the reasons that some people find stereo vision unpleasing: they receive conflincting clues about distance of objects. That's the exact same mechanism as vertigo.
(I'm happy that I'm immune to this effect, though, based on some experience of VR headsets in the past)
I'm still not sure that it's a mainstream tech, though (yes, I know... but we'll see... Google glass was also the second coming in many websites, and now wearers are called Glassholes...)