A well designed embedded systems based on microcontrollers can be very reliable.
Everything goes to hell if you need to connect to the internet or use high-level software.
Everything goes to hell if you need to connect to the internet or use high-level software.
The objective measure of what qualifies as "well designed embedded systems" is inherently gray; and where industries have seen some semblance of consensus as a matter of unconditional need, it has always been accompanied with the tears of executives complaining of non-trivial expense.
Isolated embedded systems can be like mechanical systems in that they're simple enough to be tractable and even deterministic.
A system running Linux and calling AWS lamda functions through the cell network isn't tractable.