Yeah, he says that "there was never a scenario".
But he's contradicting himself, because in a September 2015 he had this to say:
"And we have Neill Blomkamp’s Alien, which will be out in 2017. We just have the first [screenplay] draft in so far but it looks pretty good."
The script exists, both Sigourney Weaver and James Cameron said they read it, and liked it. I think Scott's trying to get all the attention to his movie.
It rests entirely with Fox whether Blomkamp's movie will be made or not. So far it seems unlikely, but if "Alien: Covenant" is a hit, I think things will turn around.
Ridley confirms it was to be called Alien Awakening
I never understood the enthusiasm for a Blomkamp Alien movie... Ridley Scott's filmography towers over Blomkamp and Scott is the one who made the original Alien as well as the cult classic Prometheus...
Why obsess over a Blomkamp Alien movie?