[Telaneo]

Because GPUs have had it soldered since the beginning, while desktops have had it slotted since (close to) the beginning. There are some exceptions to that rule, but it mostly holds.

Not to mention that the bar of acceptibility is moving. We had RAM in slots in laptops for a long while, but it's (not so) slowly going away. You can still find laptops with SO-DIMMs, but it's not a given anymore.

[Nursie]

A longer time ago, sound cards used to have expandable RAM too.

Go back far enough (486) and cache was off-chip on simms too!

[inigyou]

Yep. Soldered is just the best manufacturing process (besides on-package). Moving things close together simply delivers better outcomes and that will always trump openness concerns.

[theodric]

I would imagine that something like LPCAMM2 for GDDR is entirely possible and will never, ever be seen because people already accept replacing an entire $10000 GPU to get another 32GB VRAM on the next generation, so why give up that guaranteed revenue stream?

[inigyou]

That the highest performing option also creates the most lock-in is a happy accident.