GTA will look like that in cutscenes but I suspect average gameplay will reveal more short comings. Even if they say the trailer has gameplay that could be literally one or 2 seconds which are not quite as attractive as the rest of the trailer and it wouldn't necessarily be picked up.
But essentially yes for GTA, no for Witcher IV.
Witcher 4 tech demo is just a tech demo, and should be treated as such. The fully realised game will naturally look different as they finalise the actual content/scope and likely not hitting 60fps with Raytraycing at that quality of assets.







