Quoting Packy McCormick:

Imagine a bizarro relay marathon in which one runner carries the baton for the first 26.0 miles, opens up a backpack full of batons, and hands them out liberally to a waiting horde of sprinters to dash all-out for the final 0.2 miles. That’s the best analogy we can come up with for this moment in the Fusion Race.

which old sci-fi predictions from the first half of the 20th Century came true, and which didn’t. The answer depended on those predictions’ energy intensity.
Where is My Flying Car?
Innovations that don’t consume a lot of energy – those in the world of bits – mostly came true. Innovations that do require a lot of energy – those in the world of atoms – did not.