I think the reason why those processors are produced are because it rather makes sense to upgrade your old rig with them. Seems to be the only way actually to increase CPU sales beyond laptops ans smart phones.
I don't see more DDR4 ram being produced. Chinese brands are already starting to produce DDR5 and soon HBM. 'Bringing back DDR4' is IMHO a too bold claim.
I still use it occasionally and it's really the old CPU and worn out SSD which slow it down.
That's the plain truth: most sites/servers simply serve very very very little and have not anywhere near the need for 256 GB of RAM, let alone 512 GB.
These old servers aren't sufficient for the Amazon/Apple/Microsoft/Meta/Google/Oracle of this world, but for 99.9% of the rest of the world, they're more than plenty.
And the world and technology shall keep on marching: we'll have DDR6 and as soon as that happens, suddenly all the hyperscalers shall consider DDR5 to be oh-so-lame and dumped by the truckloads in landfills.
We may have two more painful years ahead for RAM but we'll then have plenty of used enterprise/datacenters gear on the market.
Sorry.