They'll blunder. They'll do it even harder in the absence of competition.
Businesses blunder. "The market" is just a set of observations, including that competitors will tend to take advantage of those blunders. It is not a failure of the market that businesses have blundered, nor surprising that it will happen occasionally, and neither I nor mrweasel implied otherwise.
Yes, identifying a problem is easy. But solving shortages in all cases requires perfect knowledge of future demand. So, good luck.