We upgrade RAM but not VRAM; why not?

[Carbon Copied]

Simple question really - everyone has a different requirement of how much VRAM depending on whether the placebo of more is better or screen resolutions and applications simply make use of more; so why don't GPU manafacturers make a top end card with VRAM modules you can simply "upgrade" the same as you would as if you needed more RAM in the base system?

I'm pretty ignorant to the manafacturing processes so maybe this has a bearing what is possible but is it simply a case of too expensive or are GPU manafacturers too lazy for what seems like a leap in the way GPU's are released (maybe read as it takes away an "entire" card sale on upgrading within the same gen technology)?

 

[Carbon Copied]

1) The trace lengths from the GPU to the memory are short, extending them to allow socketed memory would make the board much more expensive
2) Putting DIMM like slots on the card would destroy the air flow across the card unless you went triple slot.
3) No one manufactures DIMMs or SODIMMs with GDDR5 on them
4) If they did then each one would need qualifying and would not be cheap as they would be a boutique item (not enough demand).
5) Warranty nightmares

Seems like a waste of space really; I meant more along the lines of each actual memory module area on the board surface was a mini flat socket as opposed to a traditional dimm/sodimm slot for memory on a pcb board - buy and upgrade each socket as you go along / require (cooler re-attached locks them in place with blanks on any unused slots).

Totally get it being a niche market item and all the other reasons surrounding such a hypothetical product (that and you're limited by the grunt of the card as to how much more vram could be made use of before the next series came along).