So many items today need chips the demand may simply have outrun supply of the types needed.
The pandemic didn't help obviously, but this issue appears to have existed previous to that.
How many ICs are in the average car today?
Like a lot of things, it's complicated. Sort of a perfect storm and COVID was the icing on the cake.
Part of it had to do with some dude who said trade wars were good, and easy to win. Same dude (and admin) put a bunch of Chinese companies onto the "entity list" making them really hard to do business with. Including the Chinese fabs that were producing a lot of stuff. So one of the pressure relief valves that could have offset this was effectively closed.
Another part of it has to do with fabless semiconductor companies contracting out to TSMC [and others], and an increasing number of companies who used to fab their own stuff going that route. Companies like Apple moved away from Intel to in-house designs, but don't want to actually
produce their own chips, so they need to contract production out to a fab.
Add that to the fact that IC production, when everything is going well, is a many-month process from wafer to finished good. I think 94 spent time actually involved in wafer processing from his posts, so he knows this better than I do, but you don't order this stuff on a Monday and you'll get it on Friday. You have to have your demand planning 12-18 months in advance.
Then you put in an external shock like COVID... Where any of the companies upstream of you in the supply chain might have a 1-2 week disruption at any time, and you can't predict when or who might have it, and suddenly things start going awry.
I believe, as someone actually in the industry, that COVID was the proximate cause, not just demand simply outrunning supply.