This, I agree with.
However, I don't agree that the narrative layer 'sits on top'. I believe that a successful experience is created when the narrative layer is intricately woven into all aspects of the 'collection of interesting objects'.
'Immersion' is the key word here. A visitor experience is only truly 'immersive' when it is thought-provoking and so memorable it changes you or your thinking. This happens when the narrative pulls you in, making you confront the artists' own motivations, making you question, making you feel part of the story itself.
AR is definitely shaking up cultural interpretation conversations at the moment. The big question is whether it enhances or changes the experience in a way which is relevant and rewarding in terms of institutions' specific missions and end goals. There are certainly many applications of where it's working well, but right now there are just as many failures.
The key here is something I encounter every day at Antenna. We strongly believe that technology is not the "thing" - it's the "thing that gets you to the thing". What this means is, when the experience is so seamless that the technology moves away from being the focus (i.e. almost becomes invisible) and instead the story is the focus, we have achieved our aim.
At their core, museums are essentially collections of interesting objects with a narrative layer applied on top. With AR, the entire world is about to become the ultimate museum layered with information, visualizations and stories that help us see deeper into the history, makeup and meaning of the world we live in.