You see too far away in the future. You can’t put a tooltip in a place so that every people can see it in the exact place you put it. Nowadays the ARKit/ARCore apps have independent sessions. This means that if you put a virtual object in a lamp, next time you launch the app it is not there anymore. HoloLens has memory of places, but this memory is tailored to YOUR device.
Have a read to this interesting post. https://medium.com/super-ventures-blog/arkit-and-arcore-will-not-usher-massive-adoption-of-mobile-ar-da3d87f7e5ad When the AR Cloud will be real, what you’re saying will become true.