I like the elevator analogy. The fact is that even when prognostications get something right--they inevitably get the context, implications, and effects all wrong. That's because they get one invention or innovation right, but every invention and innovation has to be understood in the context of the million other inventions, innovations, and social changes that surround it.
So one person guesses in the mid-19th century that we will have horseless carriages in the future--but also thinks they'll run on steam engines and cause great depletion of our wood and coal supplies. Another person forsees the internal combustion engine, but thinks its only practical use will be in industry. Another person forsees high-grade steel, but thinks it will be used just for girders. Another person forsees an interstate highway system, but thinks it will be used for giant horse-drawn land trains. No one person truly predicts the automobile and its actual effects and implications. No one person puts it all together.
That's why all these reports that come out predicting the future (beyond the obvious) always crack me up. Such arrogance. About the only prediction guaranteed to be accurate is that the future will be far different than any of us can possibly imagine.
Yup.. how the heck you'll ever get that 2 inch high 20 Megs HD in that watch, I dopn't know