While that may be true, I don't think the game engine needs to be rewritten for the PS5. They got RT working in the engine and did some improvements with lighting. Also, it's sort of weird to think that they will port the PS4 game engine implementation for the PC and start from scratch with a PS5 engine that isn't portable to the PC.
With regards to the features you mentioned, we all need to be careful that we don't assume just because Epic came up with Nanite/Lumen that other studios will be just as capable. I'm not saying Insomniac isn't capable, but I'm saying that we shouldn't think all other games coming out (from various developers) that are just for PS5/XSX/PC will have an equivalent implementation just because we are in a new generation.
To add RT or the DualSense stuff to a past gen engine is basically nothing for game development compared to the paradign shift changes of things like Natite and Lumen or the stuff Cerny talked about.
We're talking about engines that don't need LODs anymore, not needing tricks like normal maps, ambinet occlusion, baked lighting, shadowing, etc because devs will be able to throw there super detailed models and textures and proper real time illumination. And all this done streaming a super fast speed allowing to stream the content of a room in the time that the door is opened, or even stream what it's behind the player in his same room as he turns to see it.
There are tons of huge paradigm changes involved for engine programmers, game programmers, artists or game designers or level designers. Phil Spencer was right when said that the technology of this generation will mean the biggest change for game development since moving from 2D to 3D games. This time we aren't talking only about being able to have slightly more polys/tris, texture sizes, resolution, framerate and some small new trick to fake lighting, shadowing, reflections or stuff like that.
As Cerny said, in the old system with HDDs and extra bottlenecks there were maze-like level design patterns or using tricks like elevators or slim corridors to hide the streaming and popping, or with stuff with walls, rocks, trees, buildings or big terrain changes in height or direction etc. to keep you a certain amount of time in certain area before you were able to move to (or see) other one that still wasn't streamed. And quite often the "door" to go back to a previous part of the level got stuck/broken/closed/etc and other tropes to don't allow you to go back (to free that part of the level from memory), or you went down through a cliff than later you can't go up.
In the same way, there's the part of damaging or destroying the environment. With all the tricks to fake detail, lighting, shadowing, reflections etc that were used in the past, to destroy let's say a wall of a dungeon would be a mess because many of these baked things would 'break' and their baked tricks would be visible. Now if objects are really super detailed and there is a great lighting, shadows, reflections and so on everything calculated in real time things are very different and there is no problem of breaking the wall of a dungeon in a random point and see proper light from the sun entering and properly changing the lighting, shadows etc. Or to allow you to move or interact with props that in the past where static not for level design reasons but to don't break any trick.
Unreal Engine 5 has been the first one to show a first iteration of this with Nanite and Lumen running in consoles, the other next gen engines are still working on it. The game teams are still learning, testing, prototyping, adapting everything to this. We're still a few years away from seeing the first games using this stuff, and a few years more away from them mastering these things and bringing the level design and game design to take advantage of it in the games where it makes sense.
Until all these things are ready, we're getting released AAA games made with the engine designed for last gen consoles, made using the same workflow than in previous gen consoles, that were started to be developed in 2017 or 2018.
) Perhaps something similar to the one we got for Horizon Forbidden West, with a couple of new gameplay segments thrown in:
cogconnected.com
