To be fair, nobody has upgradable memory in any system that has enough memory bandwidth and compute power to run LLMs with decent performance. It might be interesting to compare against some decade-old x86 server or workstation stuffed full of LRDIMMs to reach 1.5–2TB of RAM, but the bandwidth would be only slightly faster than a desktop today with high-end DDR5: nowhere close to GPU bandwidth. So performance would still suck.

Designing for extreme expandability comes with pretty steep tradeoffs.