He is talking in hypotheticals, he says it himself.
I am not sure of the benchmarks, but from what I understood from the Linus video, even with 4 Gen 4 NVMe M.2 in a raid plugged into the PCIe port, due to the bottlenecks in how the OS (even Linux) handles the I/O requets, it looks like the PS5 custom SSD @5.5GBps, with the I/O magic using dedicated chips, it seems to beat even PCs today, and that's why it's making noise even with guys like Tim Sweeny from Epic.
Here are the custom chips the PS5 seem to be using:
Dedicated DMA Controller
Dedicated Decompression Chip
2 I/O Co-processors
On chip SRAM
Coherency chip ( which link to the GPU Scrubbers in the diagram as Cerny informed )
In terms of brute numbers, even if the Aorus offers 15GBps, in the end it seems like the architecture of PCs is limited for this use case, and the change in architecture in consoles may feed back into the design of gaming PCs in the future.
Here is the linus thread which I found interesting, discussing this subtle point: