They have to plan their production in advance, with budgeting, contracts, and prices decided before the products are even manufactured. This is hard to do even when you're just trying to plan for the demands of legitimate buyers.

But every single day in the meantime, RAM prices will continue fluctuate, and arbitrage takes advantage of this. And arbitrate markets don't even necessarily track new RAM prices, if someone dumps a bunch of used LPDDR devices in China, people may harvest used memory for arbitrage.