Everybody knows it's about those games that come 2-5 years after release
For ps1 it was final fantasy 7 , silent hill, mgs
Ps2- Mgs3, god of war 2, shadow of the colossus (and I argue kingdom hearts because that game ran very very smoothly with super crisp cutscenes and colorful animations).
Ps3- last of us, mgs4, god of war 3
Ps4- horizon, last of us 2, PT
(Actually Silent Hill, Metal Gear and God of war have been staples for graphics and story for playstation, just noticed)
I'd say for ps5 well notice a graphics gap by 2022 for certain
But the threshold for graphics is minimal at this point, moore's law plays into it. We're at the point now where games are basically gonna have big graphics jumps on the systems more than ever. Well have a crazy detailed beautiful game like ragnarok right and then in 2025 we'll probably have some shyt you'd genuinely expect from a playstation 6 come crush the buildings. At some point we'll have a plateu with photorealism and it'll be more about games having super huge depth (realistically bigger maps, massive amounts of enemies keeping up with frame rates, hyper detailed animations, deeper control schemes).
Just let things develop.