Largely speaking across technological trends of the past 200 years, progress is nowhere near flat. 4 generations ago, the idea of talking with a person on the other side of the country was science fiction.
You might want to recheck your example. Four generations ago would be my great-grandfathers. They were my current age around 1920. The first transcontinental (not just cross-national!) telephone call took place in 1914.
majewsky|4 months ago