Car companies are just few percents of MCU market. A car may have a lot of MCUs, but that's probably less than 30 per economy car. The entire car industry is a drop in the ocean for The Big Semi.

On other hand, I've seen very expensive STM32s being used in near semi-disposable goods.

Car companies are doomed because they required special "automotive grade" MCUs, which are usually just very long running die series with a lot of testing.

Being on old die users, they can't share the benefit of much larger mainstream MCU die batches. They are now in the end of the queue waiting for big batches of dies for mainstream MCUs to finish manufacturing.

IMHO, lots of auto parts uses automotive grade MCUs without any particular necessity. It's just because they were well moneyed, and they can. Some Mercedes car literally have one MCU per button, which just sits on CAN bus, and blinks an LED.