Obviously not true that they’d overwhelm modern databases but feels like that place has had the same opinions since the 1960s.
The most recent desktop I built has it situated directly below the standard formfactor x16 PCI slot.
That would be possible even on spinning harddrives as long as they're already spinning.
The fastest memory can't prevent the real reason games take so long to the menu: company logos. The Xbox can already resume a closed game within a few seconds, loading a simple main menu is trivial in comparison.
Virtual memory subsystems in operating systems of the last 40+ years pretty much do exactly that – they essentially emulate infinite RAM that spills over onto the external storage that backs it up.
Prosumer grade laptops are already easily available, and in 2-3 years there will be ones with 256-512 Gb as well, so… it is not entirely incoceivable that in 10-20 years (maybe more, maybe less) the Optane style memory is going to make a comeback and laptops/desktops will come with just memory, and the separation into RAM and external storage will finally cease to exist.
P.S. RAM has become so cheap and has reached such large capacity that the current generation of young engineers don't event know what a swap is, and why they might want to configure it.
It's not that much of a stretch to imagine ultra dense wafers that can have compute, storage, and memory all in one SoC.
First, unify compute and memory. Then, later, unify those two with persistent storage so that we have something like RAM = VRAM = Storage.
I don't think this is around the corner, but certainly possible in about 12 years.
Pretty much every modern CPU is a hybrid design (either modified Harvard or von Neumann), and then there is SoC, as you have rightfully pointed out, which is usually modified Harvard, with heterogenuous computing, integrated SIMT (GPU), DSP's and various accelerators (e.g. NPU) all connected via high-speed interconnects. Apple has added unified memory, and there have rumours that with the advent M5 they are going to change how the memory chips are packaged (added to the SoC), which might (or might not) lay a path for the unification of RAM and storage in the future. It is going to be an interesting time.
This is why I always recommend developers try using SQLite on top of NVMe storage. The performance is incredible. I don't think you would see query times anywhere near 20uS with a hosted SQL solution, even if it's on the same machine using named pipes or other IPC mechanism.