As said already, this specific chip cannot support socketed memory. And personally, I don't really think Framework needs to enter the regular desktop hardware market which is already well-served by a thriving ecosystem of multiple hardware vendors collaborating around a well-defined standard (ATX).

The "Framework Desktop", with this specific choice of hardware, seems to be more of a competitor to the likes of the Mac Studio than to anything that could already be custom-built today anyways. While I think its naming choice might be a bit poor due to it being conflated with that desktop market, I think it's a natural fit as something fairly laptop-adjacent and thus close to Framework's existing efforts and strengths.