"Reed Richards Is Useless":

The TV Tropes article points out the absurdity of fictional situations where the characters invent supertechnologies to solve really hard problems in the plot, and then they put these new tools back in the box and you never see them again, even when these tools could solve other problems in the rest of the world.

I've noticed this in the Star Trek franchise, which tempers my nerd grieving over Leonard Nimoy's True Death. The various series have shown transhumanism in general, and radical life extension in particular, in a bad light. And in the original series, the Spock character, seconded by Dr. McCoy, often said that they had to stop the enhanced bad guy, or keep him from living forever, no matter what it takes.

Yet when a main character, other than a Redshirt or a walk-on, needs revival or rejuvenation, why, the ship's doctor can figure out how to do that. Yet these successful techniques mysteriously don't become part of Starfleet medical practice.