Amara's law is a maxim stating:

We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run.

It was put forth by wikipedia:Roy Amara of the Institute for the Future. It is sometimes called Saffo's law or Clarke's law.

It echoes a quote by wikipedia:Joseph Licklider that says:

A modern maxim says: People tend to overestimate what can be done in one year and to underestimate what can be done in five or ten years,

which occurs in a footnote on p. 17 of Joseph Licklider, Libraries of the Future," MIT Press, 1965.

Similar bias is also caused by the hype cycle.

Source: wikipedia:Amara's law