Sure, old carbie with distributor might've just ran with 3 cylinders , but that also might damage something.
Also auto makers don't really want to give user sensible error messages or even just metrics because without experience they might just misinterpret it as different problem.
For example if car have oil pressure gauge it is either nearly fake or heavily filtered. Oil pressure changes according to load but gauge going up and down might cause user to think something is wrong with car...
A car is not an iPhone - if the car can move at all, it must move.
The alternative could be freezing to death. What if I am driving in rural Siberia, or Canada, and there is no phone signal to call for help?
Sure, that doesn't necessarily invalidate your argument, after all this increase in car complexity (through "electronization" and smartification of more and more components) without the increase in debuggability/repairability is IMHO a bad trade-off for many consumers.
Case in point, our second-hand 2011 Ford Focus has a problem with the electronic steering assist. Apparently it somehow experiences some kind of over-voltage and the internal system shuts down. It's likely due to humidity. (So probably it's simply a design/manufacturing/QA issue.) Okay, but there's no way to get the actual data from the integrated electronics from the steering system, but it's possible to reflash a different firmware on it. Which resets the internal data. Which basically clears this error state, and the car will happily use it.
But there's clearly a mechanical error, there's a new "bad" noise when turning the steering wheel. But it's a 10+ year car, rarely used, and replacing the steering system is about ~1000 EUR, doing the firmware flashing was ~30 EUR. (Finding the guy with the laptop, who can flash the firmware through the good old ODB port was the challenge.)
And it's basically a big (market) information asymmetry problem. The car industry wants to sell more cars. Sure they sell some parts, but the more repairability a car has the less parts it really needs, as consumers can make their own tradeoffs.
So shutting it down certainly seems sensible.
