Sometimes it's also just a matter of opportunity.
I've always contended that there's a ton of career 3rd liners who could be 30+ goal scorers if they were simply handed "superstar minutes" i.e top line minutes with the best line mates + top PP time.
Of course if there's another player on the team who deserves that spot more, you never get it and it becomes an unbreakable, self-perpetuating cycle. You don't produce without those minutes and then never earn those minutes.
Give a guy an opportunity whether via injuries or poor depth and you see these late career breakouts like Miller, Verhaeghe, Marchessault, Reinhart, etc. You look at what a guy like Hyman is doing with the best winger job in the sport, riding shotgun with McDavid.
You don't get drafted 8th overall without having a ton of skill. You get the opportunity to ride shotgun with Johnny Hockey on the top line and voila, you can produce.