Watch the UE5 demo. Realize what they're doing. They're loading the high-detail geometry into the GPU and letting the GPU do the mesh reduction. For that to work, huge amounts of geometry has to be loaded into memory the GPU can see. The PS5 is built for that. The GPU has access to the same memory (24GB) the CPU does, and, presumably, so does the SSD controller. So you can put vertex buffers in files and load them directly into the GPU if you want.
On the PS5, a Blu-Ray type drive is optional. Are you going to have 100 GB downloads from the network? That's going to take a while. Even if you have a gigabit network connection, it's going to take 15 minutes or so to download a large game. Few people have that much bandwidth. Red Dead Redemption 2 needs 150GB of disk space now, so games are already that big.
Games will have to have some starting level that keeps the user busy while the downloader pulls in content. But after that, performance should be impressive.
The whole storage architecture (not the SSDs alone) is a generational leap in gaming because it's a generational leap in game production economics. Asset cost has been skyrocketing for modern games, and the slate of storage technologies in these consoles directly addresses that. These improvements make assets reusable. SSDs + built in compression / storage co-processing + dynamic resolution makes it possible for small teams to plonk high res assets from libraries into games without spending crazy amounts of time doing asset performance optimization.
It's also going to be a driver of 1440 and 4k gaming, because there will be more games that look good enough to make high res gaming worth it.
