This is all just conjecture from what i've seen having stalked NMS pre-release, but pretty sure the original no mans sky that was in trailers and early gameplay videos was lost in the flood of hello games office about a half-year prior to release. I think they were forced to keep it hushed and remake the entire game within the few months they had left before the set release date.

It would make a ton of sense. Features that were shown in trailers were not in the game. The game itself felt early stage, very vanilla/alpha.

No mans sky was worked on for years before release, what i played seemed like something someone could do in a few months. I compared the game to trailers as i played it, they looked completely different.

Granted things are supposed to be changed in the development process but it almost felt as if someone looked at no mans sky a bunch and then made something as similar as they could to it.

Now, being years after release, the game seems to have the image and function of what the trailers promised (which i assume was the original game). It only led me to believe this theory more.

They lost the game, were forced to keep quiet, rushed through remaking the game to release on time, then finally were able to finish the game with various updates.