I'd look at the comparison more like: a gear is a component (eg, cpu). If it breaks, it breaks and is not expected to be repairable, but that component should be replaceable; you shouldn't have to throw away the whole watch just because one gear broke.
But a replacement gear can be manufactured out of commodity materials using standard tools and a bunch of esoteric skills. A replacement LCD display is never going to be something a skilled worker can recreate from scratch. Your best case is that you are able to salvage matching parts from another instance of the same device - so if you have one laptop with a broken screen and another with a busted CPU you can cannibalize parts to make a single working machine.
