Yeah, you have to dig a little, because the NES wasn't discontinued until 1995. If you dig into wikipedia you can see quotes that put units sold in the range I quoted in the late 80s.

In 80s vs 90s?

I'm unsure how comparing sales of hardware vs a few years sales of a console 30 years ago is of any use whatsoever!

Because VR headsets have been selling for ~5 years.

Comparing them with the full lifecycle of the NES sales instead of its first 5 years is not a proper comparison.

I'd go further than that - VR headsets have only been properly selling for about two years at this point. The Oculus Rift didn't officially launch a consumer version until mid-2016, as did the HTC Vive, which launched around the same time. While Oculus headsets have been available in some form for five years, everything before the 2016 launch were prototype development-kit versions that came with a big asterisk on the order page saying they weren't meant for general consumer use.

Lots of enthusiasts did buy the Oculus DK1 and DK2 Rifts, but CV1 was the first time it was actually available in stores and marketed as being ready for consumer use.

Why compare them to NES sales at all?