The Jaws effect
A classic non sci-fi example is Jaws (1975). With a couple of buoyant barrels pinned to the mechanical shark, keeping it meters below the sea, filmmaker Steven Spielberg was able to tell an entire story without the shark actually being present — because most often, it was actually at the mechanic shop being repaired.
The barrels inspired more terror than the shark did! The threat of the thing was scarier than the thing itself. This basic principle was clearly utilized on the Star Trek: The Original Series episode in question, "Errand of Mercy," which forced audiences to fill in the blanks with their own minds when Ayelborne rescues Kirk and Spock from the dungeon. Perhaps that level of trust is why the fans were so loyal to the franchise from the get go.
Modern-day Trek could learn a thing or two from this because it has a conundrum: new series have an allotment of episodes (often 10) per season, but arguably enough money to make at least 20 episodes of The Next Generation — maybe even 30 of TOS.
And yet, there is a better way. The writers are certainly not fools, but large budgets can go to the heads of the best of people. Perhaps there is no responsible way to spend millions of dollars on a single episode of Strange New Worlds, for instance.
However, imagine an episode of today's Star Trek with no CGI. How would that work? TOS, despite its groundbreaking visual effects at the time, didn't have the luxury of using CGI back in the 1960s. With a minimum of tweaking, though, several episodes of modern-day Trek could have gone without Computer-Generated Imagery at. I doubt some fans would think it a crime. And if there is money left over, why not make a few more episodes?
For more Star Trek content, visit the Redshirts Always Die Facebook and X pages.