Yup, but maybe they'll get there. Valve was able to get a "custom" chip for their Steam Deck, so it's possible Framework could get big enough to get socketable CPUs. But yeah, the priority there should be incredibly low, since replacing the entire motherboard is acceptable (at least to me).

I'm guessing batteries are a bit less expensive to order custom since there are so many slightly different form factors among various devices. If it was prohibitively expensive, I'd expect to see more standardization.