[rokdog49]

Most of these explanations, while valid, really don’t answer your question fully.

If a commodity is in high demand and sells out, the exhausted inventory creates a void.
That void cannot be filled until the inventory is replenished. The seller is at the mercy of whoever supplies the commodity. Now this is where things can get tricky.
During the Oil Embargo of the eighties, anything manufactured with petroleum or petroleum by-products, went through the roof price-wise because the raw material supplier (oil company) could not get sufficient crude to refine.
They simply were forced to charge more or they would have suffered huge losses.
The theory is, higher prices=reduced consumption. Guess what, some people had to stop buying stuff made of oil.
Today, we have a surplus of oil and the oil companies have to compete with each other to sell their refined product. That drives the commodity...”crude oil” down. There is too much and only so much can be stored so it has to be gotten rid of.
Production is cut back accordingly to accommodate the lack of demand and still make a profit. Right now, we have excesses with certain commodities and shortages of others. The micro chip shortage issue is huge.
Checked the price of used cars in particular lately?
New cars are up in price and some models aren’t even available.
Supply and demand.