Do the memory makers not have a contract in place for an order this large? I assume that they aren't going to take "trust us bro" as good enough for several million dollars in orders, and even if there is a way to cancel the order it won't be free. I would assume so at least, but i would like if anyone knew for certain.
I was interning at a company that made networking gear that was put out of business when their largest customer canceled an order within a week of the delivery date.
The customer ran out of money. In terms of where you are in line of debtors when you haven't even delivered the product to a customer, it's so far back as to be assured you won't get your money.
If the memory makers got a deposit from OpenAI as part of this deal, that is likely to be the only money they will get for any undelivered memory, particularly if OpenAI runs out of capital.