@david_chisnall @thomasfuchs Edited the post a bit. At least in Sweden, many 486 computers with 4 MiB RAM were sold around 1994–95: that probably ended with the release of Windows 95.
@david_chisnall @thomasfuchs One may look at IA computer magazines to get an overview of the market at a given time. 4 MiB was perhaps most common in 486 laptops in 1994, but also entry-level desktops could have that configuration. https://archive.org/details/ByteV19N9
Hmm, I was skimming, so the first laptop I saw had 8 MiB of RAM but was also advertising enormous battery life. The next system I saw was page 133, which offered the same bundles with 4, 8, 16, and 24 MiB. Typically, when people make listings like that, the cheapest one is there to catch people's attention and the second-cheapest is the one that they expect to sell the most. The next one I found was on page 269 and also had 8 MiB.
My 386 laptop was apparently released in 1991 and had 1 MiB soldered to the board and four SIMM slots that took matched quads, so supported up to 5 MiB total. That was slightly high, most 386s I encountered had 4 MiB. My school computer room was all 386s with 4 MiB (all booting from a floppy and running everything from a file server over Token Ring, which was really slow when 20 machines all tried to launch Windows 3.11 at the same time).