It doesnt quite work like that. Sure next gen can play the games at a much higher level however old PCs can still run games today. I was running an i7 2700k and a 2gig GPU and played DOOM 2016 (which i couldnt believe i was running it, it was on low settings at 30 frames however it wasnt a broken game and i manage to play though the whole game). If Scorpio gets the support than dont be suprised that next gen games will release as waterdowned versions.
My take is if next gen happens in the next 2 years and that the foundation of Scorpio is very good. Digital Foundry were mind blowned when they saw it. There are very good signs so far for the system.
Also i dont believe Developers will just straight up jump on the new next gen numbers. Thanks to the growing PC community Devs will obveriouly want there games to run on PCs aswell and will require them to base there level of performance off the average PC user. The next Xbox 2 will most likely be a boosted Scorpio (Like a PC Upgrade) where all the games will share the same eco system. Not sure with PS5. My guess it will be your normal Generation jump where they will start fresh, however by doing that means you lose alot of the past benefits.
Actually, it doesn't work the way you are suggesting due to the way that console optimization works. Developers always develop/optimize for baseline hardware and they don't bother with scaling very much on consoles. What you are suggesting is that the developers will use Scorpio as their baseline hardware and they will scale up with Ps5/x2 which would be nonsense. And if you are suggesting that they would scaledown to Scorpio and use ps5/x2 as base level hardware, that would also be nonsense due to the performance uplift of base level hardware. The reason is the entire point of a new generation is to have base level hardware which the developers can optimize on. So if the developers will use the ps5/x2 as baseline hardware, they will take advantage of the performance uplift which the Jag won't be able to keep up with.
Yes, we have games which do fine with older hardware like an i7 but that is also due to most games not taking advantage of the wealth of performance pc hardware delivers because it is being held back by console hardware. But when the next gen get that uplift, developers will use that ryzen based cpu to it's full potential and running games on old hardware at playable framerates won't be as possible. At least for high demanding games anyway.