Would you want a realist Tetris?
If you want a big factory you need "poor" graphics. Factorio is about efficience, not about realism. Visual effects aren't the game. Calculating rotations and raytracing takes a lot of time. Factorio massively uses short tables of precalculated values, dramatically enhancing the perfs but limitating cam effects. it's a neo-oldschool game... This is the end of graphic enhancements and the come-back of real good games ideas
remember "Archipelagos"? Try it.
I'd rather play a pixellized game that can hold an "infinite" number of entities than a poor-coded visually realist game like Cities:Skylines, where your city is (very) limited by your computer perfs : a good ol' 65535 (vehicles) is a limit, lol. So it aims to be used for big cities, but can't, because bad choices at all levels make the game require high-end GPU&CPU and a lot of RAM. It's a game "by/for" graphists. Factorio is a game "by/for" devs.
In the performances/aesthetics balance, Factorio chooses the performances. The content, not the style. Factorio can run on "smallish" (for a gamer) configs, and I hope that if it's graphically enhanced there will be ways to remove ALL useless "beautification". Devs tend to think that all their potential players are hard-gamers using a high-end computer... But the complexity of Factorio comes from the simplicity of its mechanisms. Like Chess vs Go, you know...
So: Useless perf-eating aesthetics are for toys. Realism has nothing to do with Factorio (everything else is just a toy) and has to be minimalist. What is relevant is not pixellized non-moving trees, smoke, or shadows, but the game mechanics. Allowing the maximum extension for the Factory.