People used to do this as recently as the 1990s. They'd buy supplies like ice and generators, transport them to the disaster area (often clearing any debris in the road so they could get in, which helps everyone, including emergency vehicles), then sell them at market prices.

They were arrested for their efforts: https://www.econlib.org/library/Columns/y2007/Mungergouging....

So now instead of letting incentives help them, people in disasters have to rely on charity and the state. (Both of which can do their job in addition to market incentives.) The end result tends to be more shortages rather than fewer.