While I appreciate your choice of examples to make your point, I'm not convinced that pulling a slab of electronics out of your pocket every time you need to know the local time is already the peak of perfection.
A lot of people I know don't wear a watch, so yes, I believe that watches are becoming more of a niche thing.
As for the optimality of the solution: of course wristwatches aren't perfect. Let's just not sound silly twenty years from now when everyone is wearing brain implants (or a nuclear-powered fax machine necklace).
