Scaling up is much easier than scaling down.
At what resolution PS2 can play God of War 3 or GTA5 from PS3 ?
Answer: IT is not possible to scale down resolution enough to cover technology difference and asset quality.
You make game assets and graphical technology for 4TF machine for 1080p and scale up to 4k res.
You make game assets and graphical technology for 10-12TF machine at 4k and scale it down to 1080p.
Both have different cost despite looking similar on surface.
One is taking PS2 game and running it on PS3 hardware.
Other one is taking PS3 game and running it on PS2 hardware.
This is why if 4TF console exist then they will be making 4TF games as a base and scale those up to 10-12 TF rather than making 10-12TF games and scaling them down to 4TF.
Well to be fair, half of GTA5 was from the PS2
You're comparing taking a game completely optimized to run on the PS3 cell architecture and making it work on the PS2 Emotion Engine architecture, to a developer building two different optimized spec levels into an game on two consoles with identical architecture at the development level. Those are very different circumstances.
Scaling down is simple, you just pare back. Scaling up is much more difficult unless the higher quality assets were created in advance. If they were already built why wouldn't they have just built them and scaled down? Even back when I used to fart around with Maya making car models it was a very simple process to take a detailed model I'd made, then just reduce triangles to get a final useable product with just minor tweaks to the wireframe. Taking a low poly model and increasing triangles required smoothing as the added triangles still followed the harsh angles on the low poly model. Effects were the same, I could disable various textures like specular and diffuse maps , bump mapping, reduce light sources, etc. It was really simple to do back then and modern design tools have advanced drastically in ease of operation (Less time stumbling around the software means more potential earnings) Artists don't make assets aiming low, that would be a waste of their time and talent, they make assets that both fit the aesthetic they are aiming for with a final spec in mind. If they have to lower the triangle count and texture resolution to meet performance goals it's a lot easier to do that than to find out you had headroom and could have had more detail or fidelity in your assets after the fact.
You start a game high and work down to spec on consoles the same way. Game assets are created as meshes and scaled down, or optimized, to scale to the hardware specifications. You aren't just paring back resolution, you're also paring back texture resolution, anti-aliasing, anisotropic filtering, draw distances, volumetric effects like fog, sun shafts, reflections, LOD change distances, lighting effects/RT ray counts, etc, as needed to optimize the game to run stable on the platform. Most of those can be adjusted on the fly from a workstation through the development software.
It's very similar to how you can take a PC game running 4K/60 that tanks an OC'ed 2080ti/i9 equipped PC and with some settings changed have it perfectly playable on a potato slapped together in 2010. The power difference can be way more than the difference between the Lockhart and the Series X.
This is why minimum specs exist on PC, it's basically the bare minimum required for the game to operate well enough to be playable as intended and stable. The product developers advertise is the game using max setting because that's the game they built, aimed as high or higher than current hardware allows, but you have the option to turn everything down to play it on PCs in multiple performance ranges. They are still the exact same game though. Devs don't build the PC game around the worst PC on the planet, they kindly inform potato players they are shit out of luck and let the guys that can barely play your game know they can play the game. It's actually not that hard to go below minimum specs through programs like profile inspector and play the same game on a laptop, it's just not going to be anything close to what the developers deemed the minimum experience.
With consoles, developers have their artists build all the assets, engines and basically the entire game on PCs at the studio and use the dev kits to test the game in pieces to quickly figure out how many triangles/effects/post process effects the final product can have so they can optimize the game for the end hardware as they go. If the Lockhart does end up being a thing, it will be exactly the same thing as me adjusting PC game settings, only it will be for a fixed 4 TF hardware spec and a separate pre-set for 12TF implemented at the development stage. The Lockhart and Series X will likely both share identical architecture so having a game work on one will literally be scaling down graphical settings and resolution at the factory level. My guess is if it exists Lockhart will be a 1080p/reduced settings/no ray tracing console that will play every game released for the Series X.