I agree that charging 200 bucks for a flat of water will ensure a supply of water. Most likely that same flat of water, because water is fairly simple to replace during record rainfall.
With gasoline it’s not so easy to replace.
If the price is raised to $20 a gallon what prevents the desperate from simply commandeering those pumps?
The police.
So, if the government is offended, then the police won’t help.
The power to hold life in hostage for greater pay is replaced by the power of people banding together to overcome what they see as threatening their lives.
Ultimately, gouging will lead to rebellion.
In a hurricane, or a civil disturbance, the state and local governments are quick to impose "order," which in their sense of the term means closing roads, evacuating non-essential personnel--which would include most of us old fogies--and figuring out where the stock of essential goods is located so it can be requisitioned when the time comes.
Show me a director of FEMA who has ever had experience in the real world, taking a risk on ordering stuff that may or may not be sold at a profit. There aren't any.
Government employees know nothing about purchasing, inventory, insurance, cost of labor, licenses, permits, regulations and myriad other details that come with running a business.
How, then, do we expect emergency workers to micromanage a suddenly-disrupted economy whose working they have next to zero direct knowledge of, other than as a consumer?
I won't argue with you about gasoline being more difficult to come by than water, most of the time. But are out-of-state tankers likely to want to resupply Florida gas stations at great personal risk for the usual price? And, if those same stations can't raise the price at the pump to cover without being fined by the state, what reason is there for them to stay open once they run out?
The market economy works in mysterious ways, too complex for even educated economists to fully understand. I've only touched on one small element with the gas station. Multiply that by a large number of daily transactions, locally and nationally, then throw in world commerce and you have a really complex system of trade, for which we should all be grateful. We'd all be without shoes and hungry without it, just like they are in Haiti.
Although it was written many years ago, Leonard Read's I, Pencil is one of the most amazing short stories I've ever read. If you haven't heard of it, you will benefit greatly by reading this short essay.