Competition.
You're correct that this is true, but wrong in that it is not relevant.
SOTA fabs are used for cutting edge CPU/GPU chips. You do not need a SOTA fab to create DDR5 memory or SSD memory. There are a number of companies able to create the lithography machines to do so, and dozens of actual operators of those machines.
RAM was this price some years back, and yet last summer/fall it was at an all-time low.
Will we continue to see steady improvement in top quality CPU/GPUs? Would they even bother releasing consumer versions of ram faster than DDR5?
The current generation is insanely fast. I am planning to get a gaming PC for my wife and a mix of gaming + workstation PC for me (or maybe just base it off of the Ryzen 9950x3D and call it a day). We plan to hold on to them for 10 years.
I don't care if anything 6x faster comes out. For what I need the current generation is even an overkill.
I'd even go as far as to say that it would be quite OK if that's the very last generation and no further hardware development ever happens.
My dream spec is UE5 at 120hz on an 8k oled. I think that sounds like a super sick experience I would buy tens of thousands of dollars of hardware for.
Happened before, will happen again.