My point wasn't to encourage 8051s in cars; it was to say that many, many types of fairly mundane MPUs can do the work needed for most of the car's subsystems. Yes, Cortex M0+ chips are just fine for this, and are (relatively) blazing fast.

I know Tesla was able to pivot to different MPUs during the shortage, because the code is pretty much decently layered; so only the Low Level code to wrap the peripherals needed to change.

It's true, it's hard to replace MOSFETs when you have 1KV / hundreds of amps needs --- however, it is possible to make MOSFET arrays using lower-capable parts.

Obviously, infotainment and AI-ish tasks are not what I'm talking about.