I was editing that old article from my old site awhile migrating from HTML 2.0 to WordPress when it made me realize the AMD64 CPU et al have the same problem. Not enough address pins.
The AMD64 only has 48 pins, so that affords 256TB of address space. RAM for some extreme projects I can think of is a problem.
Unfortunately AM4 does not do anything to fix this shortcoming. I would have liked 64 address pins.
Expanded memory, extended memory. Bank switching. This is why I hate short count on address pins.