I share the sense that “flaky breakthroughs” are common, but also… I mean, it clearly is possible for people to learn and improve, right? Including by learning things about themselves which lastingly affect their behavior.
Personally, I’ve had many such updates which have had lasting effects—e.g., noticing when reading the Sequences that I’d been accidentally conflating “trying as hard as I can” with “appearing to others to be trying as hard as one might reasonably be expected to” in some cases, and trying thereafter to correct for that.
I do think it’s worth tracking the flaky breakthrough issue—which seems to me most common with breakthroughs primarily about emotional processing, or the experience of quite-new-feeling sorts of mental state, or something like that?—but it also seems worth tracking that people can in fact sometimes improve!
I do think many of the historical people most widely considered to be evil now were similarly not awful in full generality, or even across most contexts. For example, Eichmann, the ops lead for the Holocaust, was apparently a good husband and father, and generally took care not to violate local norms in his life or work. Yet personally I feel quite comfortable describing him as evil, despite “evil” being a fuzzy folk term of the sort which tends to imperfectly/lossily describe any given referent.