Memory factories cost billions to tens of billions, "investors" aren't going to spend that kind of money if they are not reasonably certain that they are going to make a profit, and the market is very uncertain right now with everybody bracing for a bubble burst at any moment. It's not the first time there has been such a shortage in the computer parts market, and the oligopoly, be it RAM or hard drives manufacturers, has always managed to keep prices high and production low enough to avoid a price crash after recovery.