Not quite true. Although very wealthy people could afford to pay a high price for fuel for frivolous reasons, most people (even the wealthy) would tend to avoid doing so. So if a middle-class person were planning on using fuel to go on a road trip, they might postpone or cancel the event, which would help to ease the demand. Whereas if a relatively poor person were planning on using the fuel to go on a road trip - to attend the funeral of a loved-one - they might decide it's worth any cost and go anyway. Hence the people that need the fuel the most are able to use it, whereas the people who merely would like it are not. This extends to far more important operations: If an organ-delivery service needs the fuel to get a living heart from a donor to someone whose life depends on it, they're able to pay the added cost. In a system where prices are fixed too low to quell demand the heart patient will pass away due to lack of availability of fuel. It's literally a matter of life-or-death that prices be able to rise to quell demand.