I tried to edit and create buildings in Google Earth 4.3.
(Because I used slow PC, operation is awkward.)
You can delete buliding freely with right-clicking on 3-d model and select "hide building", and create new object with polygon menu. If you have Sketchup or other 3-d software, you can put more detailed object, too. Oh, it is metaversed!!
Google Earth will be widely used as a very strong, free platform in the field of the visual environment simulation.
Only a geostationary object can be put now. However, various interactions will be added by using the script such as kml and LSL in the near future.