For one, they could have could have not massively scaled back consumer memory manufacturing as a matter of duty to customers. But money and greed must prevail.

I'd come at this from a different angle: we still want this to be market system, so we need to make this priced into the market. How can we price this in?

I would try to solve this by making the market structure reflect the underlying difficulty: we have to decide what capacity to produce years in advance, to construct the memory fabs. So this should be a futures market, and a capacity crunch would affect short-term-futures, but leave full term futures at the same price. Because the companies supplying the memory can just construct more capacity to fill those futures at the same cost regardless of the AI demand.

I think the epic mistake was made by investors and executives who bought tales about imminent super-intelligence about to displace millions of knowledge workers from entire industries replacing them with AI datacentres.

These people are the main reason why AI companies have unlimited funding, and can afford to buy global RAM supply for years in the future despite their expenses exceed revenue by billions.