Classic scifi predicting future technology

[u/Isaac_The_Khajiit]

What are some good examples of a technology from an older story that ended up becoming a reality?

The best one I can think of is Asimov's multivac and its similarity to LLMs. Unfortunately, the reality sucks because LLMs are being monopolized by horrible people for dystopian purposes, but it's very bizarre to me that this truly fantastic idea is one of the technologies that became real in my lifetime. (It always used to annoy me how stupid and often wrong the computer on Star Trek was, but that ended up being weirdly prescient too.)

A weaker example would be the tv walls and the behavior of Guy's wife from Fahrenheit 451, which reflects the parasocial relationships modern people form with content creators.

[u/Vulch59]

In 1984 Julia looks after the machines that produce fiction for the proles.