The long-term question isn't whether people want a watch or something more generalized, it's more a question of whether your wrist is a viable place to wear something useful. Traditional watches and the plethora of UP/Fuel/FitBit bands seem to say "sure."
Any disruptive technology starts out less effective than the thing it's disrupting. Early cell phones were big, clunky, and had short battery life; early smart phones had clunky keyboards and low bandwidth; early SSD drives were (are) more expensive and smaller than HDDs, etc. Early smart watches have and will continue to suck at being watches, but that's not the point. When battery life is no longer an issue, when clunky tiny interfaces stop trying to replace bigger interfaces and focus on things that work well at that size, *then* the disruption will begin in earnest.
Various posters are correct that a Rolex is a fashion statement and that its time-telling ability is incidental. However, there is such a thing as fashionable technology, so for the luxury watchmakers to think that they're completely immune to disruption looks short-sighted to me.