A lot of the games are cross-gen titles, plus a lot of indie games showed off where graphics aren't really the focus. I think the "true" next-gen titles do look spectacular, especially Horizon Forbidden West. The amount of detail is unlike anything I've seen.
I have written about PS5's specs in the past. You can expect CPU around a Ryzen 5 3600X, GPU around RTX 2070. But that's not the full picture, as it brings next-gen tech not available on current PCs. Also, the SSD is insane, faster than even the highest-end PCs today, and with in-built compression tech, it can do about 8-9 GB/s effective. Most SSDs on today's PCs do about 0.5 GB/s, the premium SSDs do about 2.5 GBs, and the cream of the crop around 4 GB/s. This is crucial and why you can see an incredible depth of detail in the Horizon Forbidden West trailer, if you look closely. This is because assets can swap in and out of the VRAM in a way games simply haven't done before and can't do on any PC available today.