So if what your saying is correct, it's infact worse that it just rendering at 3840x1608 and 24fps.
The actual game being likely to be 4k30 would have had to downgrade from those visuals given the reduced metrics it was running at, but your saying it's likely not even that, it was smoke and mirrors really... so not near representative of anything?
Disagree about horizon FW there's clearly for me some gameplay bits in there, looking at HZD and what it did on a PS4 its not hard to see some of those shots being achievable. Bgs has said as much that it was cinematics plus some gameplay shots without hud and camera moved out for max cinematic effect.
Heres the bits I think are gamplay some with camera moved for best effect etc.
There's a few more bits but that'll do. guerrilla aren't going to embarrass themselves by showing something that not even representative.