Just played with the sandbox, and it seems like 16% of Apple users wouldn't consider buying Apple VR headset even for $3,5. I don't think even the lochness monster would be so stingy.
The answer seems plausible with that interpretation.
If you went out with a VR headset and offered 30 minute demos of them to random people for $3.50 I don't think you would have an 84% success rate.