I found this extremely thought-provoking, and I feel like I see this dynamic in some aspects of social activism. It’s really hard for people to accept that something has genuinely improved, and they don’t need to fight so hard for it anymore (and can turn more attention to things that haven’t improved).
Do we think that a problem persists even when it has become less frequent? Levari et al.
show experimentally that when the “signal” a person is searching for
becomes rare, the person naturally responds by broadening his or her
definition of the signal—and therefore continues to find it even when it
is not there. From low-level perception of color to higher-level
judgments of ethics, there is a robust tendency for perceptual and
judgmental standards to “creep” when they ought not to. For example,
when blue dots become rare, participants start calling purple dots blue,
and when threatening faces become rare, participants start calling
neutral faces threatening. This phenomenon has broad implications that
may help explain why people whose job is to find and eliminate problems
in the world often cannot tell when their work is done.