Accelerating substitution across eras
The telephone took roughly 50 years to achieve 50 percent penetration in developed countries (1880-1930); radio accomplished the same milestone in 25 years (1920-1945); television in 10 years (1950-1960); the internet in 5 years (1995-2000); smartphones in 3 years (2010-2013). Each technology adopted faster than its predecessor, compressing the timeline from generational shift to mere years.
This acceleration reflects several factors: larger addressable markets (billions of people versus millions), network effects (a phone is useless without others to call, but each new user increases utility for all), manufacturing scale that reduces unit costs, and pre-existing infrastructure (radio and TV rode on electrical grids already installed; smartphones used cellular networks laid by telecoms).
Saturation and displacement of predecessors
Fast adoption also means fast displacement. Television replaced radio as the dominant entertainment medium within a decade; smartphones made cameras and music players obsolete within five years. This destruction of older technologies happens faster than society can fully adapt, creating waves of economic disruption.
The S-curve pattern is consistent: slow early adoption, then exponential growth as critical mass is reached, then plateauing as the addressable market saturates. Disruption to older industries happens in the steep middle phase when adoption accelerates. This is why technology transitions create winners and losers so quickly.