We are not nearly far enough in the gen to make any meaningfull comparison between real life performance between series X and PS5. There is more to both device than their ability to render flops. When multiplatgames are made specifically for both might be a good comparison. Also the series X exclusives could be held back by the series S in the long run. Everything on the series X also needs to run on the series S. Which could also be a factor why the real life gap will not be as big as the paper might suggest. Or perhaps the difference will become bigger the further we head into this gen. We simply don't know what the future will hold and whether or not its relevant. Diminishing returns are also a thing we need to consider. I can barely noticed the graphics difference in demon Souls between RES and performance. But having 60fps is pretty sweet.
Please excuse my (probally) poor grammar