$3k keeps the limited units out of drawers and in the hands of people that will be making something with them.
This device has a lot of cameras and scanners in it. After they work out what is actually required and used the consumer model may have fewer to control cost.
Apple will deliver an app or two to set the user experience quality bar, it sounds like VR conferencing is one of those, but that doesn't mean they think that is what the device is for. It is just that they need to give an example of what the user experience should be or you will have developers delivering poorly performing, battery eating, usability disasters and customers will think that is inherent to the device.
How many people can afford at least 2 AR headsets? Not many, but also not too few. Engineers who flock to the Bay Area and leave their parents/families in other countries can afford that, and will - if AR calls will offer an immersive experience.