Is there anything (technically) preventing SBC manufacturers adding SODIMM slots?
I was expecting the Milk V Titan to avoid this memory nonsense since it has two unpopulated DDR4 slots, but it has fallen off the radar like several other SBCs.
DDR4 is also crazy expensive right now so this just depends on you having some around from a previous build
SODIMMs are huge compared to a BGA memory package which is a problem if your goal is to minimize your board size (e.g. I don't think there's a reasonable way to fit it into a Raspberry Pi form factor without something weird and expensive like a mezzanine connector). Routing the signals is also somewhat more annoying because they all come out of one edge of the connector compared to a BGA package which has them fan out in every direction, giving more space for length matching traces, etc. You'll likely need additional PCB layers compared to a BGA chip.