[philwelch]

“Demand goes up so price goes up” is true ceteris paribus. For instance, if the FDA banned Ozempic tomorrow, you would expect the price of food to go up because many of the Ozempic patients would return to their previous consumption habits. But there have been a thousand other things that have happened which adjusted the price up and down, and most of those events in the past 200 years made food cheaper instead of more expensive, because the world increased the amount of food it was able to grow a lot faster than people increased the size of their appetites.

In fact, this actually demonstrates another effect: as something becomes cheaper, people will consume more of it. Strictly speaking, demand is a curve where quantity demanded is inversely proportional to price; if “demand goes up” we usually mean the entire curve shifts to the right. There’s also a supply curve: quantity supplied is directly proportional to price. The intersection of these curves is the market price; nobody “decides the prices” unless you have a monopoly or cartel or government interference.

Housing, incidentally, is a classic example of government interference.