Well IMHO anyone on higher end 4000 series shouldn't upgrade at all. It's not any shocker that 5080 is slower than 4090. This release is more for folks still on 2000/3000 series. And if you need VRAM then 5090 is: YES.
Me personally maximum CUDA and VRAM which makes 5090 obvious jumping from 3090 for 2.5x rendering uplift/card. But we'll see still plenty of optimizations when it comes to compute in next 4-6 months so it may be even nicer. For gaming surely nobody needs 5090.
As another poster mentioned earlier on, this would be the FIRST ever generation where the x80 card fails to match or beat the consumer flagship card of the previous generation, so even if it's not surprising due to the spec leaks/reveal from NVIDIA, it's still extremely disappointing.
Looking at TPU's own Relative Performance data from GTX 980 onwards:-
GTX 980 was 11% faster than the GTX 780TI
GTX 1080 was 31% faster than the GTX 980TI
RTX 2080 was 9% faster than the GTX 1080TI
RTX 3080 was 36% faster than the RTX 2080TI
RTX 4080 was 30% faster than the RTX 3090
Even the much maligned Turing based x80 was faster than the previous flagship and that generation was considered a colossal disappointment, so what does that make Blackwell lol.