You said overkill though!!
The demo has no RTX or Hairworks enabled,so imagine what the game will run like at 1080p in its current state with those on even with an RTX2080TI?? BTW,with the example you have given its 2.6X(if my maths is right) and the game is also probably CPU limited to a degree at 1080p. So to get 60FPS at 4K is probably going need something like at least two maybe three of the RTX2080TI cards I suspect.
No doubt the game needs a ton of optimisation but it also might come with a side effect of the visuals being downgraded.
If you look at The Witcher 3 pre-release demos they looked much better than the final game,so it seems CDPR toned the graphics so they could run better on consoles and midrange PCs.