I have a story on point. My brother is a manager at a company which installs electrical and HVAC systems, working mostly with very high-end private homes. They had this couple as clients, both very fancy architects, who designed their new home to be completely computer-controlled, from window shutters to air conditioners to lights, without any physical switches (I guess there was a remote and sensors or something). The architects had this theory that physical switches completely ruin the aesthetics of a room, and wouldn't abide having those horrible things in their dwelling. My brother says that he practically begged them to let him install backup physical switches - his proposal was that they would have a large panel in a closet somewhere with switches for everything in the house, which would still leave the switches hidden, but would at least make the house usable, if not very convenient, if the computer failed. But the clients insisted on no switches at all and the vendor of the computer system was willing to work with that, so that's what got built.

Anyway, about a month after the project got handed over, my brother gets a call: the computer had somehow worked itself into the state of "beyond fucked", the new computer brought by the vendor was refusing to talk to the controllers, parts were backordered, long story short, the house had been unlivable for a week with no end in sight, and could my brother come over and save it somehow. I think he was able to turn on a few of the most critical things on in manual mode, but obviously he couldn't wire up the hundreds of electrical devices in the house. Not sure what happened later.