An alternative hypothesis would be adaptation:
According to adaptation theory, individuals react to events, but quickly adapt back to baseline levels of subjective well-being. To test this idea, the authors use data from a 15-year longitudinal study of over 30 000 individuals to examine the effects of marital transitions on life satisfaction. On average, individuals reacted to events and then adapted back towards baseline levels. However, there were substantial individual differences in this tendency.
Perhaps some of the epiphanies really are transformative. But the individuals may quickly settle back toward a happiness set-point.
LW doesn't seem to have a discussion of the article Epiphany Addiction, by Chris at succeedsocially. First paragraph:
I like that article because it describes a dangerous failure mode of smart people. One example was the self-help blog of Phillip Eby (pjeby), where each new post seemed to bring new amazing insights, and after a while you became jaded. An even better, though controversial, example could be Eliezer's Sequences, if you view them as a series of epiphanies about AI research that didn't lead to much tangible progress. (Please don't make that statement the sole focus of discussion!)
The underlying problem seems to be that people get a rush of power from neat-sounding realizations, and mistake that feeling for actual power. I don't know any good remedy for that, but being aware of the problem could help.