Scaling according to demand is way too hard when it comes to silicon.

Nvidia might've been planning to eventually buy them back from the miners, or sell software RAM unlocks.

The card was initially priced at over 4 grand and it had its capabilities severely reduced to make it not compete with real GPUs.

Plus: most of those cards probably have broken RAM chips anyway. Throwing them out would be a waste, limiting trash chips to a small amount of RAM that does work turns recycling costs into a product that can be sold for money.

The marginal cost to fabricate the GPU die with the full ram allotment, and then disable a portion for 1) salvaging otherwise useless die's with partly bad ram for lower ram use cards; or 2) market segmentation; is tiny compared to the marginal cost of creating X different masks and fabricating X different die's, one specific to each market segment/ram size amount.

In addition, fabricating the same die for every SKU point in the product line means the maker does not have to guess how many version X vs. version Y vs. version Z dies to fabricate. The just have one fabricated. Then the dies become SKU version X, Y or Z as demand requires during the card assembly process.