Oculus sold a lot of users but most of them were used 0 or 1 times.
This product will need to be actually useful to take off, the early adopters need to rave about it to their friends. Presumably that's why Apple is targeting such a high price point at first, I'm sure they could remove half the cameras and use a worse CPU and end up with a device that sort of works, but first impressions matter.
Maybe in very niche cases, but there's a lot of dead bodies on the VR/AR hardware hill even there with Hololens, MagicLeap, etc.
Then again Oculus sold like 20M units, so who knows...