Yeah, you're not getting the goal. They are using actual data from the areas you're flying over. You're suggesting they look at it like a game, where the reuse textures and models. Their goal is the opposite, to have the game look like the real world.
Even in MFS2020 my house roughly look like my house, and the taller structures look like they do in my city, they aren't just skyscraper#93781 and bridge#12381, they are all unique structures that uses the bing maps data to look just like it does in real life. The landmarks in my city are my cities landmarks. They aren't just generic buildings.
The fact that you started by comparing it to GTA 5 makes it obvious you don't know, but okie dokie, at this point I have to assume you're just trolling.