That's not the issue, it's having mutiple players in the same location at the same time. The procedural generation will be the same, the networking makes a big difference. There's none in Megatron Rainfall.
Nope, you must be imagining things because nobody has said that, I would like to see a post from someone saying it's impossible.
It's doing it realistically with weather, plants, animals, people, buildings, fire, the whole lot as a believable world, nothing less will do. The difference between Elite and games NMS, as good as it is, is that a ELW in Elite should look as close to the real thing as possible where NMS uses cartoony style graphics. Why do you think SC is having so many problems, it's the issue of realism, they are trying to create the entire thing in one hit and are still in Alpha after how many years? FDEV are proceeding bit by bit to produce what they can and developing as they go, the full pressure earth like worlds should get here eventually, but trying to do everything at once isn't going to work. it's quite likely if FDEV went ahead to do the entire lot in one go and have everything done including realistic earth like worlds they to would still be in Alpha.
And that's part of the problem isn't it, physics verses magical superpowers, the Elite Galaxy is an attempt at modeling the galaxy and physics as close as practicable, what you have in Megatron Rainfall is just some sort of magic. Are the solar systems modeled realistically, do they orbit the sun, do they model weather and rainfall and rivers and the ecosystem with any sort of accuracy. There's a huge amount of work under the hood in Elite Dangerous just getting everything to run together in a way that's as realistic as possible in a computer game, Megatron Rainfall just ignores all that and uses magic, so while it's quite an achievement for one person, it's not a galaxy simulator and all that entails.