An old maxim says that people tend to overestimate what can be done in one year and to underestimate what can be done in five or ten years.
People are also very poor at predicting long range effects of novel technologies.
To a large extent this is caused by the slow rate with which new approaches are adopted by society. Even in the age of the internet, changes that affect basic habits of working and thinking do not occur overnight. As a premier example, Mathematica has had a great impact on scientific research and communication, but the full gains from it will take a long time to emerge. The Impending Demise of Traditional Scholarly Journals and The Decline of Unfettered Research. Odlyzko has also written numerous technical papers in mathematics, computer science, and cryptography.