Did you know that Microsoft released a 3D world map with the ability to look at any part of the globe from any angle? Roads were mostly accurate, as were rivers, lakes, and islands. There were thousands of highly detailed 3D models of significant buildings and landmarks, and over 20K highly detailed areas. Of course, since it was Flight Simulator 2000 those 20K areas were airports and your house almost certainly wasn't one of them. I was on the team then and it was a pretty significant accomplishment at the time. We used digitized satellite data, digitized topographical maps, survey data, government data, and some 3rd party content to make the world look real.
A few years after that Google Earth was released and Microsoft, in true fast moving tail lights fashion, needed to have one. So a small group of us left the FlightSim team and went over to the newly formed VirtualEarth team to build a 3D world in the browser. We did that too. C# management in an ActiveX component over Managed DirectX. We used FlightSim data for roads, rivers, airports and all of the landmark 3D models. It was cool and all, but not many people cared. They didn't have the interest, need, graphics card, or internet bandwidth to really use it. And the world was pretty flat. So we bought a company that made aerial cameras and turned the imagery into a 3D model and helped them scale up. Oh, and we put a very simple 6DOF flight model in the rendered so you could fly around. No cockpit/instrument panel/navaids, but it felt "airplane-like". So Bing Maps is a direct descendant of FlightSim.
By the time MS sold our part of Bing Maps to Uber we were building 1 meter or better resolution 3D models of the world from 5 - 30 cm resolution imagery. We were generating our own road networks. We incorporated data we derived from street level imagery to get road names, turn restrictions, speed limits, and business names/addresses. Because we needed a routable map for our users.
And here we are in 2020. Microsoft just released a new version of Flight Simulator. This time outsourced to a 3rd party developer. And guess where they got their data? Bing Maps. So a new game, with a highly accurate 3D world, built from satellite data, aerial data, government data, and user generated content is now available on-line (or as a 10 DVD box set).
So we've come full circle. FlightSim started from existing maps then turned into a map with VirtualEarth/Bing Maps, and now Bing Maps has turned back into FlightSim