There are a lot of reasons why suppliers might not match demand.
Let's say you have a factory that runs at 90% utilization and somebody crawls out of the woodwork who wants to order 3 factory-months worth of widgets, delivered next week.
Well first of all, you cannot meet that schedule, so you turn away the order in the instant case.
Now the question is: if we were to scale up production, what is the chance that some new person will crawl out of the woodwork with a similar instant order once the factories are ready? Because if we judge what has happened a one-off case, then we will refuse to meet the demand, whether it is real or not.
(Of course we're also making a lot of simplifying assumptions here like that you have access to capital, that there is no regulatory issue with scaling up production, that increased production does not open you to new lines of attack from your competitors, etc. Which are not good assumptions in general.)
It is our judgment of the demand, rather than the real demand, that controls production. If we are manufacturing, say, kevlar vests in 2001, we may very well interpret a large order as representing an underlying demand shift. On the other hand, if our widgets are luxury cars in 2008, we may interpret a similar set of facts as a one-off order.
The insight here is that real demand is not known at the time that supply is trying to meet it; it is estimated. The extent to which the market clears depends on how good the estimation is. With something like oil we understand demand fairly well, but in markets like consumer electronics the demand predictions are poor. That is why on the one hand Apple is chronically short of iPhones and simultaneously Amazon cannot give its phones away: all the estimates were off.
In short, the more your widget is impacted by technological or cultural shocks, the more likely it is that suppliers won't adjust to meet demand.