The problem is that is speculation and the market barriers are currently too high for losing business to be a threat. The two outcomes are (1) you overbuild, you end being wrong, you go bankrupt and lose everything or (2) you are right, but since you didn't overbuild, you lost out on some revenue, but demand still exists 3 years later and you didn't lose everything.

In any other business choosing (2) would mean someone else swoops in and steals all your business. It doesn't look like this is at all possible for memory fabs.