They should just provide an AC power adapter for high power GPUs, like a laptop’s external power supply.
Why? It'll only increase the cost of the card while adding an unknown quality power converter into the mix. I'd much rather have my choice of PSU then leave it up to the GPU OEM's profit motive. As well as someone else mentioned if you're buying a 4090ti with a potential cost of 3-4 grand springing for a 1000-1200 watt PSU shouldn't break the bank. If it does then you really need to reconsider your build priorities IMHO.