As I said in one of my threads, all things being equal, they need another 8 yrs to get to a final release. EIGHT FUCKING YEARS MORE
When you need 15+ years for developing a video game, your underlying platform is gone, when you're done.
In eight years, their engine will be legacy cruft and DirectX11 is long gone - as is the hardware supporting it, and Windows might be too.
It's like starting a large Amiga 500 game project as a single person in 1990 working 30 years on it and then release it in 2020: The result will only run on emulators if at all.