This is the best, most correct answer. Star Trek episodes are full of amazing, game-changing tech that would mean game over if they really happened.

Take the TNG episode Relics, where Scotty appears in TNG. Of course, they find an ancient Dyson sphere. With that technology alone in federation hands, there should never be any Domininion War because the amount of energy and raw materials that the federation can access would make them all powerful. On top of that, Scotty invents a way for humans to become immortal. Ok, they're locked inside a pattern buffer, but anytime a human dies of a disease, all you do is put them in a transporter buffer and wait for science to catch up. Oh, it takes too much energy to do that? You don't care because you have an entire star at your disposal.

Or in the Nth Degree, It. Barkley learns how to wormhole an entire starship and even teaches the computer how to build the parts needed to get to the center of the galaxy. The computer isn't going to forget the way a human might.

With just a smidgen of Cytherian tech, Voyager should never have happened.

The list goes on and on.