Well, besides the games that use RT. Like AG's results it depends on the game. These numbers are nice and prove that really any "entry level card" with 8GB of ram should be at $200 or so, $250 being generous as none of them are really gonna be great for more than two years.
Also, while I get his testing method of using the same cpu/mobo just changing pci-e limits, I don't agree that those older pci-e 3.0 systems will be cpu bottle necked. Certainly not anything Intel 9th or 10th gen nor Ryzen 3000.