At the one hand you have a point. Semiconductor production can be quite specialized, and an accident at a fab can completely halt the production of certain products for years if not permanently. This is what happened to AKM[1] not long ago.

On the other hand it seems unlikely to me that auto manufactures would allow their portfolio to be so exposed. If this accident had been more like the AKM fire, I'm sure Kia would have found a replacement chip.

And as others have pointed out, it's not like modern ICEs can be made for sale without quite a lot of advanced electronics.

[1]: https://www.audioholics.com/news/fire-destroys-akm-audio-chi... (also see comment from "Matthew J Poes").