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.