"Detroit" farmed out a critical component to a byzantine JIT supply chain and let their bean counters sample from a smorgasbord of overly specific SKUs, half of which vanished the moment the system experienced a little stress. Nothing to study here; employ some grownups to whip the children into line. Given the relatively primitive fab nodes these manufacturers deal in there is absolutely no reason they couldn't have been manufacturing their own silicon devices in a cost effective manner or at least secured supply through contracts, except that they're all run by cowardly, shortsighted c-suite seat warmers.
it's much worse than that. i've posted on this before. you have to understand the semiconductor manufacturing process. automotive grade is unique:
1) the cost pressure is much higher
2) the speed of components (max clock rate) is far lower. even 16 mhz is 16x faster than actually needed
3) the current and voltage is 100 to 1,000 times greater than those used by ICs used in the average consumer product. 50V and 10A to drive a Fuel injector.
4) the usage conditions are unbelievably hostile: sustained ambient temperatures of 110C are normal and the EMI would fry a consumer-grade IC in seconds.
therefore it is not only laughable to expect to use consumer-grade 45nm Foundry geometries or lower, it is just flat-out stupid. in 3D printing terms it would be like using a 0.2mm nozzle to 3D print a 10ft x 30ft x 5ft object: stupid.
it should therefore come as no surprise to learn that automotive grade ICs are typically manuactured in 250 nm. no consumer-grade IC goes anywhere near this dumb-sounding geometry. it should also come as no surprise that the layer stack is also completely different.
only a handful of Foundries in the world have - had - the capability to manufacture 250 nm. the masks (made of glass, stored at the Foundry) were not allowed out of the Foundry, even though they were paid for by the IC designer. they wouldn't fit a competitor's Foundry anyway.
and then shit happened. orders stopped.
now, one crucial aspect of Foundry equipment is: you can't ever stop. you cannot let it cool down. if a Foundry has no orders, which they hate, they run blank wafers to keep the equipment up to temperature.
what do you think happened when 40-year-old equipment suddenly received no orders for 18 months?
they scrapped it, didn't they?
all these morons had to do was keep on ordering parts, even just a trickle. except, i don't know if you're aware of "Factoring"? letters of credit? with all the big car manufacturers ceasing orders, all the Factoring also ceased. so none of the suppliers could guarantee that they would be paid, so of course they stopped manufacturing.
bottom line is: it is the cessation of credit facilities (Letters of Credit) from the AAA+ rated companies like Ford, GM, Chrysler, that is actually the underlying cause of the collapse. the rest is just consequences.