2. This isn't like a monopoly on water supply, because the ships don't have to go this way. To make the analogy work you'd have to add something like "everybody already has a well, but supplying tap water is cheaper than using a well". In such a situation, a water company that's maximizing profits would charge just a little bit less than using a well, and while it would annoy people it wouldn't harm them.

3. The government stops water companies from gouging for the good of the citizens, which isn't a factor here.