Impressive wall of text, but you still haven't explained why a ~10% difference in FPS is so meaningful. You can always turn one setting down from ultra to high, and you've got that 10% back - not that you notice 10% anyway.
I actually explained it in my wall of text. You should read them, as you may become enlightened.
Let's put this another way. Next gen is almost-certainly going to use 36gbps and 40gbps memory (with similar cache structure to what nVIDIA currently uses, albeit it might be a L3 instead of L2 etc).
They will likely be 6144sp/12288/18432sp. This would be equalized to 3780 or 4200mhz, probably 225/450/675W spec.
It likely the 36gbps SKU will actually just have some shaders disabled per die (say 1920 instead of 2048).
For instance:
6144 @ 4200/40000 = 9070 xt @ 3150mhz. This is fast-enough to meet the spec I have explained going on 3000 times for RT.
5760 @ 4000/36000 = Still faster than the capability of 9070. It would likely OC to hit 50TF. This would be under 4400mhz, and within the capabiltiies of overclocked 36gbps ram (even Micron, potentially!)
Hope that simplified it for you. 9070 will be obsoleted right away, and it already kind of is. It's just that not everyone plays games with those requirements yet.
It's okay...I know when those games come out everyone will complain. But the point is that is why I am explaining it to you...So you know it's coming and don't make a bad decision.
This is also why 9070 will eventually be very cheap; same for 5070. Because it (and they) do not meet those requirements. That is absolutely fine for *some* games, but it won't be great in many games.
Again, I think many people see these purchases as investments meant to last 4+ years, or more than one generation. I think it's possible we see more of those games wthin the next couple years bc XB if not PS6.
That's all. Just saying...if you can be prepared, and it doesn't cost a lot more, you should. If you don't want to be, or that is not a priority to you, that is your prerogative. I'm just giving a heads up.
Ofc you can turn down settings (or scaling level) to an extent, but that hassle isn't worth the $50 imho if your experience can be better. And I truly think it will be, because everything points in that direction.