Read again carefully. The QD dev is comparing advantages of SSD to games before, including PC. "Games before." It removes a bottleneck from mechanical drives. There is no comparison to Xbox. People keep seeing system wars when there isn't any. I've talked to a couple devs including a multiplatform dev using Unreal Engine 4. Graphics do not scale linearly with more SSD speed. SSD throughput matters but a delta doesn't automatically give you better visuals. Depends on your bottlenecks for the type of game you're making. You need compute for geometry...as well as everything else. When you run out of compute, you're not loading more geometry by using SSD magic.
Today, including PC, youre bottlenecked by how many assets you can load quickly no matter how much compute you have to draw more. They get around this with masked or traditional load times.
Is there a type of game that could be made exclusively for the PS5 that will run best there thanks to the super fast SSD? Possibly....if you're moving through environments that are highly detailed yet low in geometry, physics, collision detection or overall interactivity. A walking sim could really shine. If you can thread that needle between needing the entire throughput capability while not running out of compute on the PS5, then that same game will need to reduce asset detail or increase pop in to compensate on other platforms.