I have a feeling that CDPR are intending to go over to a two different game development system, like so many other game companies are doing. Where roughly every other two, or three, or so, years they release another game.
I am looking at companies like Bioware and Bethesda here... where they release a Fantasy game, and then X years later they come out with a Sci-fi game, and then X years after that they release another Fantasy, and then another Sci-fi, etc, etc.
If this is CRPR's intention... to switch back and forth between two different game series like this (or maybe genre)... then I actually think this would sort of fit in with the idea of that they are intending to release two AAA games in the time from now untill 2021.
That way CP2077 would maybe come out in 1919, and this other unknown AAA game would come out in 2021... and then maybe a CP2077 2 would maybe come out in 2023, and a nr2 of the other AAA game would come out in 2025, etc. That would give each game roughly 4 years of development time, not counting what ever time they might have spent on preproduction already befor that.
Alternaticly they might go for a 3 years between each game instead... which would give each game 6 years of development time (again, possibly not counting the preproduction of the game)... compleatly depends on how long they wish to spend on making a game befor releasing it.