GoW 2 or Halo Infinite 2 are just examples of games coming to next systems (presuming the names follow simple conventions of course). A more pratical example would be, say, Horizon Zero Dawn 2 (or whatever it's named) which will likely release in 2021 or the next mainline Forza, also likely a 2021 title.
In any case, the point is that even games released in that launch period seem immediately infeasible on the previous hardware unless they started their life there in the first place. A notorious example is Shadow of Mordor's PS3 version missing a crucial element of the game (the Nemesis System). This was a 2014 game btw. The new hardware will enable devs to employ ever more complex systems, AI, routines, denser maps, denser crowds, etc. Depending on what the game is and what the point of said systems is, keeping yourself tied to the previous gen might just not be possible at all.
Which is why I find this notion of keeping games tied, even if for a year or two, to the previous gen by force a bit....odd. Unless all devs are willing to work around that (either by keeping things simple, making different versions, whatever really) it seems a bit...limiting. At least that's how I see it.
