However, I can't fully agree that generating 3d scene "on the fly" is the future of maps and many other use cases for AR.
The thing with geospatial, buildings, roads, signs, etc. objects is that they are very static, not many changes are being made to them and many changes are not relevant to the majority of use cases. For example: today your house is white and in 3 years it has stains and yellowish color due to time, but everything else is the same.
Given that storage is cheap and getting cheaper, bandwidth of 5G and local networks is getting too fast for most current use cases, while computer graphics compute is still bound by our GPU performance, I say that it would be much more useful to identify the location and the building that you are looking at and pull the accurate model from the cloud (further optimisations might be needed like to pull only the data user has access to or needs access to given the task he is doing). Most importantly users will need to have access to a small subset of 3D space on daily basis, so you can have a local cache on end devices for best performance and rendering. Or stream rendered result from the cloud like nVidia GDN is doing.
Most precise models will come from CAD files for newly built buildings, retrospectively going back to CAD files of buildings build in last 20-30 years(I would bet most of them have some soft of computer model made before) and finally going back even further - making AI look at the old 2D construction plans of the building and reconstructing it in 3D.
Once the building is reconstructed (or a concrete pole like shown in the article) you can pull its 3D model from the cloud and place it in front of the user - this will cover 95% of use cases for AR. For 5% of the tasks you might want real time recognition of the current state of surfaces for some tasks or changes in geometry (like tracking the changes in the road quality compared with the previous scans or with reference model), but these cases can be tackled separately and having precise 3D model will only help, but won't be needed to be reconstructed from scratch.
This is a good 1st step to make a 3D map, however there should be an option to go to the real location and make edits to 3D plan by the expert so that the model can be precise and not "kind of" precise.