Yes the rated speed is the max. Ill concede to that.
Though I havent seen any evidence that the SN850 or Samsung 980 are hitting closer to 6GB/s than they are to hitting their actual rated max speeds.
Could you post a link to where you got that information.
And I will also concede that when PCIE5 controllers drop they would def def meet the mark as they will completely fill the throughput of PCIE4. Assuming little to no loss in throughput that would lock them to a max of approx 7.8GB/s.
If indeed only the PCIE5 SSDs truly meet the mark, the cost of expanding the storage of a PS5 would be more expensive than even the scam Series X expansion card.
Im sure....hell willing to make an Avatar bet(timed of course), the SN850 and 980Pro/Evo will make the mark its just that Sony havent got their update ready yet.
Remember the fastest PCIE3 controllers got to about 3.5GB/s peak of a possible 3.9GB/s that the standard allows.
I think at 7.4GB/s we have officially seen the fastest Gen4 SSDs.