That is because there are bottlenecks my friend.The trouble with generational leaps in modern gaming is the inherent diminishing returns of graphics and the like. The push from 1080p to 4K is barely noticeable when you play a console from across the room, but it requires significantly more computing time. Same is true with increased 3D modeling fidelity and textures. We have gotten so good at faking lighting and shadows that they often look essentially the same as ray tracing to the untrained eye. Linus tech tips just did a video testing this idea for ray tracing.
I doubt my wife could even tell the difference between a late gen PS4 game and a crossgen PS5 game at the moment.
Not bottlenecks in hardware anymore, but software. To this day we are still being offered games that have to store their textures in an individual 256MB buffer, per texture, to avoid crashing the game engines. 4K resolution needs oh so much more than that to store a proper resolution texture. You are gaming at 4k with 1080p textures at best. It is goddamn glaring every time I boot a game @4k and just look to the horizon. This is why almost every game is a tunnel simulator these days. They have to hide it. Else, you would be like WTF am I looking at GameCube graphics?
What is sad is I first noticed it way back in WoW:Cataclysm when you could fly over Azeroth in all its low resolution texture glory. I could see the checkerboard landscape stretch for miles. Cataclysm relesed in 2010. I have been waiting 11 years for the limitations in code to be removed, or at least the goalpost moved.