If they gradually increase production capacity then prices stay high for 10+ years (or for as long as it takes for demand to crash) because a gradual increase in production takes that long for them to add enough capacity for current demand.

If they add enough capacity to meet current demand quickly then if demand crashes they still have billions of dollars in loans used to build capacity for demand that no longer exists and then they go bankrupt.

The biggest problem is predicting future demand, because it often declines quickly rather than gradually.