Actually I should point out that these guys are describing the simplest level of economics.

In reality it doesn't work that way.

Take the personal computer. Demand for those is huge but the price has actually gone down over time. What happened there? Well the market adjusted and something called "economics of scale" kicked in. Basically if a company had to exist only making a small number of computers they'd do it almost "by hand" and they'd be very expensive. When you make millions of computers it's done via a highly automated process at huge factories and research costs are spread around.

I guess what I'm saying is that while in the short term a sudden spike in demand will create a shortage and higher prices, the effects of a long term increase in demand could be that the prices goes up, down, or stays the same.

However artificially controlling the price of something is liable to backfire on you. Resulting in things like scalpers and shortages.

If you really want to make something easier on the consumer there are a number of ways a government could intervene without messing up the marketplace. For example in many states some subsets of food and clothing don't have sales tax, and the government is giving out cash cards to help pay for the new boxes TVs will need as the networks go digital. Also if you don't pay attention to the formation of monoploies you can get artificially high prices. Though usually hitting the monoploy with anti trust laws is a better way than messing with pricing.