two HD texture mods for Fallout 4
HD texture mod for Borderlands 2
Far Cry Primal HD texture mod
First, what you're comparing here is not "4K" and "Standard HD Textures", but "HD Texture Mods". Made by random people from the Internets. For all anyone knows there
might not actually be a difference between the two other than that a random person took the Standard Textures, added some sharpening or manually "upscaled" them and maybe did other light modifications and uploaded them as "HD Texture Mod".
The problem here is that in most cases only the developers themselves have the higher resolution textures in storage, and most often they'll not release them for public consumption or might use them only down the line for some "Remaster" effort or whatever. In this case Modders can either take the available textures and try to edit/process them to try and "make them look better" while remaining faithful or they take their own pictures of something similar and replace the ones in the game, in which case it might look a lot better but it won't be faithful to the Original e.g.:
https://www.moddb.com/mods/serious-hd-retexture-landscape-skyrim-by-z4g4/
Second, all of your pictures are not 4K,
they're 720p and horribly .jpg compressed. How the fuck do you want to tell the difference between "HD" and "4K" textures from
compressed 720p Screenshots? This points to severe user retardation, like watching 4K movies on a shitty 1366x768 TN Laptop screen and exclaiming that you "DON'T SEE ANY DIFFERENCE AND WHAT THE BIG DEAL IS ABOUT!?!"
Cause I don't see a difference, and I don't see the point. I actually hate overblown texture sizes as they just increase the install size of a game. Your game would usually be 20 gigs in size, but you added 4k textures and now it's 100 gigs? Fuck right off with that shit. A barely perceptible increase in texture quality is NOT worth 80 gigs of space!
Nobody fucking cares if you see the difference. They're
not for you and your shitty 720p TN panel. If you ask me, they can release games that are 300-500GB if they make sure the quality is right. HDD space nowadays is hardly expensive (we are getting into affordable 18-20TB HDD and 4TB SSD territory - or at least were before Minerfags tried ruining that too) and you can download and delete shit really fast. I don't want to see any blockiness, banding, artifacting and blurry shit in either videos/cutscenes or on game textures and other assets if it ain't necessary because some retard is whining about "MUH SIZE". I'd be fine downloading additional "Texture Packs" though and having some sort of "Pleb Version" for people like you (like what console versions usually are for).
For instance I would have been fine downloading uncompressed or lossless compressed Megatextures for RAGE at even 1-1.5TB given it looked the best it could have:
https://rpgcodex.net/forums/threads/john-carmack-on-jre.129437/page-2#post-6295717 but because of space concerns on the 360 and console mouth-breathers the game was limited to 3 DVDs and ended up looking the way it did (which it will for eternity or till someone at least gets the idea to Remaster it) with blurry close-up textures even on PC despite sporting revolutionary Tech.
Instead they've even regressed since then e.g. comparison of what's supposed to be the same spot between RAGE (2011) and RAGE 2 (2019):