I think this has more to do with bad labeling. A smart watch isn't really a watch. It tells you the time, but if that's all it did, you'd just keep using your old dumb watch. We only call them watches, because the term, watch, is a familiar label for something we wear on our wrist. If the machine that you wear on your wrist didn't tell time, and it's only function was controlling the appliances and technical devices as they exist now, no one would expect them, or more importantly want them, to last longer than the appliances or technical devices that they control.