I had the idea of writing something similar, but you did it far better! One of the problems of ARCore and ARKit is indeed the fact that the experience is related to a single person. There’s no way for a shop for instance to put a virtual element inside its place so that people with an AR device can see it without downloading an app or such things. We lack the concept of a shared augmented world.
I was pretty deluded by Apple not adding rear depth cameras. The leaks preceding the events announced them… maybe we’ll see them in iPhone XX?