I can't think of any direct examples right now, but I know I've seen players over the years who spent 3-6 seasons in a lower line capacity with their 20-40 points per year and then sometime between 25-28 years of age, something just snapped (or they got a bigger role) and they were 50+ point guys from there on out.
Can see that can of thing happening with Holmstrom.
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Different times and a really different player, but I recall Derek King being like a 30-45 point guy for 4 straight seasons, then having like 3 straight 70-point seasons for the Isles before getting dealt.