Imagine you were working in development and poverty reduction in the early 1990s (I was!). Only one website existed in all the world in August 1991 (today there are over 1.5 billion). Mobile phones were expensive, rare, and clunky. Very few would anticipate a situation in which India would have more mobile phones than toilets.
To paraphrase Bill Gates: we tend to overestimate the changes that will happen in the short term and underestimate those in the long term.