If you are referring to London yes, that’s exactly right (as it stands) as bizarrely there is no 3D map data for bing of London... or in fact any of the U.K. as far as I’m aware. Although it’s a lot better done than base scenery in eg Xplane. Basically the AI is trying to recognise what is a building, tree, road, grass area etc from the 2D data and then populate it with more or less generic assets accordingly. I say more or less generic as I believe to some extent it tries to match the footprint shape, recognise the type of building, and for example if it sees eg a red roof it will put a red roof on it.
Where they have the 3D map data you get a much more accurate representation that holds up pretty well even up close. Fly around one of the photogrammetry cities and that feels truly “next gen”.
I don’t know if there is a reason why they don’t have any 3D mapping of the U.K., but one assumes in general the quality of some currently 2D mapped areas will improve over the 10yr lifecycle they were talking about as they incorporate mapping updates into the sim with their “world” updates.