They hang out at the same parties. For some reason all the car industry execs were convinced that people would buy dramatically fewer cars in 2020. Because they have a religious aversion to holding any stock they decided to shift the risk over to their suppliers, fucking said suppliers over, as the car industry normally does when they expect demand shifts. The thing that made this particular time special as opposed to business as usual is that the car execs all got it wrong, because people bought way more cars due to pandemic rather than less, due to moving out of cities and avoiding public transit. So they fucked over their suppliers a second time by demanding all those orders back.
Now, suppose you're a supplier of some sort of motor driver or power conversion chip (PMIC) in early 2020. You run 200 wafers per month through a fab running some early 2000s process. Half your yearly revenue is a customized part for a particular auto vendor. That vendor calls you up and tells you that they will not be paying you for any parts this year, and you can figure out what to do with them. You can't afford to run your production at half the revenue, so you're screwed. You call up your fab and ask if you can get out of that contract and pay a penalty for doing so, and you reduce your fab order to 100 wafers per month, so you can at least serve your other customers. The fab is annoyed but they put out an announcement that a slot is free, and another vendor making a PMIC for computer motherboards buys it, because they can use the extra capacity and expect increased demand for computers. So far so normal. One vendor screwed, but they'll manage, one fab slightly annoyed that they had to reduce throughput a tiny bit while they find a new buyer.
Then a few months later the car manufacturer calls you again and asks for their orders back, and more on top. You tell them to fuck off, because you can no longer manufacture it this year. They tell you they will pay literally anything because their production lines can't run without it because (for religious reasons) they have zero inventory buffers. So what do you do? You call up your fab and they say they can't help you, that slot is already gone. So you ask them to change which mask they use for the wafers you already have reserved, and instead of making your usual non-automotive products, you only make the customized chip for the automotive market. And then, because they screwed you over so badly, and you already lost lots of money and had to lay off staff due to the carmaker, you charge them 6x to 8x the price. All your other customers are now screwed, but you still come out barely ahead. Now, of course the customer not only asked for their old orders back, but more. So you call up all the other customers of the fab you use and ask them if they're willing to trade their fab slots for money. Some do, causing a shortage of whatever they make as well. Repeat this same story for literally every chipmaker that makes anything used by a car. This was the situation in January 2021. Then, several major fabs were destroyed (several in Texas, when the big freeze killed the air pumps keeping the cleanrooms sterile, and the water pipes in the walls of the buildings burst and contaminated other facilities, and one in Japan due to a fire) making the already bad problem worse. So there are several mechanisms that make part availability poor here:
1. The part you want is used in cars. Car manufacturers have locked in the following year or so of production, and "any amount extra you can make in that time" for a multiple of the normal price. Either you can't get the parts at all or you'll be paying a massive premium.
2. The part you want is not used in cars, but is made by someone who makes other parts on the same process that are used in cars. Your part has been deprioritized and will not be manufactured for months. Meanwhile stock runs out and those who hold any stock massively raise prices.
3. The part you want is not used in cars, and the manufacturer doesn't supply the car industry, but uses a process used by someone who does. Car IC suppliers have bought out their fab slots, so the part will not be manufactured for months.
4. The part you want is not used in cars, and doesn't share a process with parts that are. However, it's on the BOM of a popular product that uses such parts, and the manufacturer has seen what the market looks like and is stocking up for months ahead. Distributor inventory is therefore zero and new stock gets snapped up as soon as it shows up because a single missing part means you can't produce your product.
and this is how a conference call among car industry exec buddies that have convinced each other that for some reason people will buy fewer cars in a pandemic managed to destroy the entire electronics market for (hopefully no more than) a year or so