I have some amount of confidence that the sellers on AliExpress will figure out how to create cheap hardware that makes use out of all of this when it hits the secondary market.

Yes, but also no?

For standard desktop CPUs, the memory controller doesn't support the signaling required to communicate with an RDIMM. There's no clever AliExpress adapter that will magically give a component within your CPU capabilities that it simply doesn't have.

However, if you have a true workstation, you don't even need some adapter from AliExpress! Xeon 600, Threadripper 7000, Threadripper 9000 all support RDIMMs natively.