Minivans are a special case that's not a good example. Minivan's have been drastically dropping in popularity (as defined by market share)for the last 20 years. Many models have been discontinued, and remaining models are being made in much lower quantity. It's basically a very niche product at this point at somewhere around 2% of all new vehicles sold.

Now there are only really 5 models of minivan left, so any small jump in purchasing, or misforecasts by a manufacturer leads to huge backlogs.