Nirvana fallacy
Etymology
The economist Harold Demsetz named the "nirvana approach" in 1969, criticizing economists who compared real institutions to an idealized alternative. "Nirvana" is Sanskrit for a "blowing out" or extinguishing, the perfected state in Buddhism. Here it stands for the flawless benchmark against which everything real is judged inadequate.
noun phrase · /nir-VAH-nuh FAL-uh-see/
Rejecting a workable option because it falls short of an imaginary perfect one.
What it names
Spotting it keeps a real, achievable improvement from being killed by comparison to a solution that will never exist.
Example
"This vaccine isn’t a hundred percent effective, so it’s pointless" is the nirvana fallacy.
Related idea
It often rides on a false dichotomy — perfect solution or none — while ignoring the useful middle.