Yeah i think your arguments are all wrong.This isn't going to be a concern on a game design or technical level... The only concern here is a marketing one (an explanation is coming, don't worry).
Throughout gaming history, across ALL console generational transitions (with perhaps the only exception being the SNES-N64 transition), first parties have a dirty little secret that they'd rather you didn't know about...
All launch-window titles for a new console, from a first party studio, are ports from the previous console
This is a universal truth, and the first parties have traditionally tried to hide this by pretending that their new consoles make these new games possible, and that they simply couldn't have been made on the previous console; but very rarely is this actually true.
Even going as far back as the SNES we can see this phenomenon starting. Simcity is a perfect example of a game that was originally designed for NES, before having its NES version cancelled and turned into a showpiece title for the new SNES hardware. Ico was originally a PS1 game, Saturn and 32X were littered with Megadrive ports and cancelled Mega Drive games that were up-ported as "exclusives"; Gran Turismo HD on PS3 was just a port-up of Gran Turismo 4; Metroid Prime 3 and Super Mario Galaxy were originally built on modified Gamecube hardware; Pikmin 3 was originally a Wii game and so on and so forth...
I bet you didn't know that every single first party launch-window title for the Xbox One was originally running on 360...
Ryse: Son of Rome on Xbox 360
Killer Instinct on Xbox 360
Crimson Dragon on Xbox 360
Oh, and just as an added bonus...
Here is Kameo: Elements of Power on the original Xbox; basically 100% identical to the Xbox 360 version
The point I'm making here? Previously, console manufacturers have gone to great lengths to hide this truth from their customers; in order to paint their new consoles in a better light. However, this time, Microsoft are going against the grain and are not hiding it anymore. Microsoft is no longer in the business of selling boxes and pushing hardware platforms, but rather they are positioning Xbox as a service that works across a myriad of devices (including PC, mobile and Switch). Microsoft therefore, have no need to hide this truth anymore, as they benefit from making their userbase for Game Pass as large as possible.
It is standard for the first 1-2 years of a console's life to be made up primarily of first-party projects that were cancelled on previous consoles and then ported up to the new hardware; and this has been true for as long as consoles have been pushing 3D graphics (this window was historically shorter, but has been steadily increasing as game development requirements and complexity has increased over time). Sony will be doing exactly the same thing as what Microsoft are doing here; but will not be telling you that they're doing it. When they make the claim that Demon's Souls Remastered and Gran Turismo 7 could only be done with The Power Of Playstation 5; they are bullshitting you.
Sony want to sell you a shiny new box, and they will do everything they can to make you think that it's literally a gift from God. Microsoft are no longer in the business of just selling boxes; they want your Game Pass sub, and they don't really care how they get it.
Game design has not really been limited by CPU/GPU specs since the PS2/Xbox/GCN era and that is still true now; no matter how much the console manufacturers want you to believe otherwise.
_The fact that every new console actually has some "old gen" titles being lazily ported on the new one doesn't mean it's a good thing. Sure we'll always have those games, but if they were the only ones at launch, then good luck to sell your new console. If Sega Saturn only had genesis 2d ports at launch and no Viruta Fighter ? Ho i'm sure things would have went super well for it. If Snes had only NES titles with upgraded graphics ? Nah it had things like games designed around mode 7 actually and fortunately.
_ The fact that some games started development on old hardware doesn't prove anything neither. Look at that Ryse video, do you think it has what was impressive in the XBO game ? DO you think the SNES version of Mario 64 would have been comparable to the N64 version ? Or Ico on PS1 ?You're confusing 2 things there. A game starting its dev on an old hadware and a game having to run on those 2 hardware is not the same thing. Those games were actually upgraded, not only in graphics but also in ambition and scope when they shifted hardware. What if they had to keep running on the old hardware in a good enough version ? They would have been super different.