Some of this really goes to learning skills - to coachability and coaching.
I don't think
anyone wanted the defensive version of Duran when he first came up to be a long-standing feature in our OF. The question was whether his offense was sustainable and whether he could improve defensively. The reporting on both was (IIRC) that both were legitimate possibilities, but not sure things. And weren't sure things. There absolutely is an alternate-world version of Duran that does not get help (and a handle on) his mental health issues, and so implodes and is out of baseball.
Or take Houck - common wisdom was that he's a lights-out 4 inning man, tops. There, we had a longer track-record, but Houck existed in the same pitching environment (so to speak). He was changing his pitches, trying to enhance his craft, but it took Bailey to make that final change, going with his strengths to bring out this (possibly best?) version of Houck.
So, I don't think
@Cassvt2023 was nuts or anything to be skeptical of Refsnyder and his role on the team; there's a legitimate question as to whether or not he'd regress or continue. Personally, I think Ref's a bit stickier of an example than the players above - less likely to move far from his baseline.
I guess my take-away from all this is that talent can sometimes be actualized, but some skills are much harder to teach/learn (pitch control/swing judgment). When we're considering betting on players we need to keep that in mind.