I guess one reason for that may be that these prediction have usually smelled of "top-down" thinking, and ignoring the effect of people's interaction with technology has and the creative uses thereof. Text messaging, apparently, came about by accident. Mobile companies included the feature, but more as an afterthought, and were surprised by it's popularity by the masses. At least three of the things above (smart phones probably excluded) are the result of this kind of reciprocal interaction (grassroots organizing, groupthink, whatever you want to call it).