In the demo there is a scene where a guy displays some iceberg photo on a virtual screen and then moves closer to it, with the screen anchored to some 3D point in the real world.

I think they'll inevitably introduce this down the track. The idea that you can set up a workspace as fixed to a particular place. Sit on the couch, and by default it has media apps and a big screen. Put it on in your office, and you can cover the walls with reference drawings and appropriate apps that are all where you left them.

Isn’t that an intractable problem without LiDAR? I suppose the naive solution would be to fix the screens in spots as you suggest as opposed to pinning onto real life locations.

edit: ah, right the vision pro does have lidar. I look forward to seeing this pinning if it's implemented. I'm still skeptical it would work well - I've used ARKit and it's not really that accurate when you're moving around.