Example of a technology that was long underestimated?

[.Scott]

Gravity waves were theorized about a century before LIGO.

 

[Henryk]

Electric cars. They were actually quite popular at the end of the 19'th century. In fact, the 100 km/h speed record was broken in 1899 by an electric car.
They are coming back now.

 

[mathwonk]

According to wikipedia, airbags were patented for aeroplanes in 1920 and for cars in 1953, but automakers declined to invest in them until after the patent expired in 1970, so the "inventor", i.e. patent holder, made nothing. Lack of consumer interest caused their use to cease again in the late 1970's, only returning in the 1990's, after years of opposition from automakers.

 

[StatGuy2000]

In my personal opinion, I think virtually any technology in common use today was ultimately based on earlier inventions that were long underestimated. Which raises the question of the underlying process from technical innovation to dissemination of said technology across a broad swathe of the population.

 

[LeoChan]

In the book "Guns, Germs, and steel", it said the wide usage and need of technology come after the invention. While we might feel like there are many examples of the invention is to resolve something, most of them are just out of curiosity. Necessity's mother is the evolution of technology.

 

[marcusl]

Rocketry. Robert Godard had functioning liquid-fuel rockets in the 1920s, but the technology languished until near the end of WWII.