The other part there is the mod support. There are a number of quality of life things that mods can do (such as https://mods.factorio.com/mods/Supercheese/Squeak%20Through ) which become more important as the factory grows and the "physical" constraints of the game make it difficult to play at the extreme ends.
Continuing on the mod theme, there is also the "once you feel that you have sufficiently beaten the vanilla game, there are a number of ways to mod the game that add complexity or other challenges." I am personally fond of Seablock where the game is a vast ocean with a few small scattered islands. Everything is then made from water. Water -> electrolysis (H and O are vented initially) -> slag -> crushed stone -> (+ water) -> mineralized water -> ore... and that gets you started.