This matters less than you think.
That is because LTT tested games that were designed to run from spinning disks. Once the disk is no longer the bottleneck, very quickly something else becomes the bottleneck. Mark Cerny explained this very well in the Road to PS5 presentation why they need a fast SSD (between 8:43 and 9:30), and which bottlenecks they needed to remove (between 13:13 and 14:00).
This has since been mirrored in other game developers' comments. I expect that once developers stop caring for the old console generation, and start using DirectStorage on PC, a slow SSD means you will have to live with reduced detail or increased object pop-in.