There's also a whole bunch of costs that probably don't make sense if you think you're going to sell a very small amount of cards in total; you have to develop, test, and qualify the PCB for the gaming specific SKU, you've got marketing to deal with, and then presumably the cloud version and possibly even the provis version have their own driver stack, so you now have your software engineering costs to bring it into the gaming driver stack, as well as ongoing support and optimization for the same.Additional revenue implies there's a market for $2k gaming Radeons which is just not true.
It's not the memory prices, it's the PPA that kills it.
AIBs also might not be keen in paying all their own fixed costs for their own PCB development, marketing, support, etc if each AIB might only sell a few hundred.

