Define “development” - Habs had the GOAT in Claude Ruel, yet he couldn’t magically turn Alfie Turcotte, Lindsay Vallis, Brad Brown, Turner Stevenson etc into regular NHLers let alone 1st line fwd / 1st pairing Dman for any period of time they were projected to be…
Now if development is fine tuning, to get that extra 1/10 of a second for example, yes that’s definitely doable but if there was this magic potion of player development many teams would be turning chicken s*it into McDavid …
IMO too many people confuse “maturation process” of life with player development. There are early bloomers and late bloomers - but without extreme hunger / drive there will be no success.
Players who don’t develop in the end lack that elite level of hunger..