I think you will find that a lot of those art assets are copy and pasted. If you are talking about assets you can move around in then ED trumps nearly every game ever made (maybe not NMS, but the planets are tiny in NMS) by just landing on any average sized planet, then include all the planets to that too.
As to the division, that game world is tiny compared to ED, so it is much easier to fill it up with stuff. In ED you have lots of different internal types of station a number of different out sides of the stations, all the ships, all the internals of the ships, the thargoid bases, the guardian ruins, the ruined ships, all the different types of mega ships, the flora on certain planets, the thargoids, planetary bases, planetary outpost, skimmers, player avatars and all the different versions we have, the UI. I'm sure there are a lot more that I haven't though of.
Now just imagine putting all those things into a tiny map the size of the division.