As mentioned before, this problem has largely been solved. The constraints are not just waiting time, and waiting time is often the least of anyone problems. The elevator waiting time problem can, for example, be solved more efficiently with mirrors than by building more elevators. Waiting for a telephone operator is solved more efficiently with estimating time for wait and music than adding operators. So the question becomes is the line a problem to be solved, or only an issue for the stressed out suits who visit.
First, it is arguable that at a a place like burning man which is allegedly a social event, the act of waiting in line is not in fact part of the stated purpose. I mean, where else do you get an opportunity to meet random like minded people. It is why waiting in line at whole foods is not big deal. It is really party time. Only overly introverted judgmental people get all stressed over it. If one is laid back and enjoying the groove, who cares?
Likewise it is reasonable to ask whether profits would increase with more ice. The writeup postulates that there is a fixed costs to bringing in ice and that profit increases linearly for more ice sold. If this were true, then there would be more than three distribution points. So what is probably going on here is that paying people to drive and sell the ice would cost more than the profits to sell the ice if more trucks were brought in. Probably three trucks of ice is probably what is sold, and through most of the day the wait time is not an hour. Wait time would probably be reduced more by people choosing a different time to buy ice. It would probably be beneficial to track wait times during the day and see if it would be possible to even out the flow of people. If more ice is needed than is supplied, then add another truck and increase if necessary.
Finally we have the cute idea of the volunteer. In the case of price gouging the last thing one want is an untrusted person dealing with the product. You might as well ask the drug dealers to have volunteers distribute the H. The marginal cost of a bag of ice is minimal, but the bags must be sold to cover the costs. If the situation is as dire as the poster suggests, there would be a large incentive for the volunteer to steal ice. Maybe each volunteer works an hour, and then thinks they are entitled to a couple free bags of ice. At minimum wage, the firm is not making any bargains off the situation.
I know how these festivals go, and roughing it is hard, but that is why we were given granola, and way clavier is not suitable for every occasion.