The cost of the external eye displays seem absolutely crazy.
Two extra external displays in raw hardware. But worse, they are on the front in exactly the place you want to place the passthrough cameras, so now you have to do extra image processing to virtually reposition the input as if it were on the eyes. So it makes passthrough dev more difficult.
It must be extremely compelling to see those eye screens in action. It must be selling onlookers on the device. That's the only that could justify that much effort?