No offense, but it's silly the amount of focus you put on obsolete Windows versions and obsolete DDR3. I use my PCs for much longer than most people*, but I'm not going to run an EOL OS because it had a smaller base memory footprint.
If someone wants to buy small (i.e. 4GB) RAM sticks, there are plenty of used ones to be found.
* Currently I daily drive 2017 Kaby Lake, no hardware replacement plans. Linux makes it easy for geeks to use older systems comfortably. Unfortunately, Microsoft has different ideas on that.