It's seemingly absurd on the GPU given have nearly no details on changes for that - though I can hypothesize various improvements to the rendering pipeline based on the images we've seen. I know the cloud and atmosphere has been overhauled so that's a strain even if it's minuscule.
As for the CPU - that may be the way it is from the descriptions of how deep the ai and notoriety system are and they still have not detailed them in their entirety. It's not just police, it's not just gangs, it's not just the militia in dogtown; it's all of them with distinct archetypes and progression. And there are also going to be high level mercs that hunt you down for any number of reasons when you piss off enough people it seems. For that to work they've had to rework driving, driving ai, and physics among other things. And these systems have regional constraints. That's not mentioning changes to pedestrian and driving ai for civilians and Trauma Team.
Another thing, though small, are the appearance now of body physics(namely breasts). All the female body types have bones for this system, but it's turned off in the current game. I'm not sure what the specific impact is as I haven't measured it, but I know the mod that enables this across all females can produce a hit for lower end CPUs. Yes - it's more convincing than any other title at the moment.
That they're apparently going to enable this kind of irks me because I had gone through nearly every model enabling/disabling the feature based on clothing, breasts size, faction, etc for my immersion mod I wanted to release soon.... oh well.
Again; These could just be high barriers and your impact may not be that significant. All this is not happening immediately, I'm sure they will continue detailing what's coming down the line before it hits, and users on PC will certainly have a beta branch in Steam to remain on the current version of the game along with the available selection of version that Gog offers. As for Epic Store Front - well, almost the entire gaming community tried to warn people of this poison apple so... Dunno where this leaves console players.
I understand you, but unless we expect a game changing update like you mentioned above - and even then, many games have similar systems in place - I don't see it needing a 12700 for 1080p, let alone a 12900 for 4k.
That at least make some sense (having smaller CPU gaps than GPU), but it is still hard to fathom.
They would literally need to blow every other game's systems (AI, factions, etc...) to justify those specs