Also, there are ways to load only the parts of the game you might need based on a radius around the player location. Open world games like GTA V does that. You can get on the road or walk across the whole map and you will never see a loading screen of any sort. It doesn't have all the polygons and textures for the whole island loaded in memory at all times. It just loads very quickly what is going to need to render next.
Elite and NMS have loading screens. They are cleverly disguised as the jump between systems ("witchspace" in Elite and "warp" in NMS). In fact, when Elite has server connectivity problems, the jump scene takes a lot longer and sometimes it crashes before arriving to the new system. It doesn't feel like a loading screen because you keep seeing your ship and you can even look around while jumping but limited to just that, since you can't interact with your ship during the jump.
I haven't played the others in this list, so I don't know if they do the same.
