For my money, it's a confidence thing that goes back to organizational priorities and questionable commitment to development. The confidence factor is tough to measure but I believe it is real. I mean Lafreniere had 10 points in 5 games in the WJC in his pre-draft year. Small sample size sure but that translates to a special player in the vast, vast majority of cases.
The trajectory that most other 1OA picks the last 20 odd years typically follow has been shattered (junior stud -> top pick -> significant if not top role in the NHL on the ice and in the locker room).
Kakko IMO is similar. Look at this clip of PP work starting at 1:10 here, I believe Kakko's first preseason game:
Yes that is actually Kakko working the right half wall on the PP. Looking to aggressively make plays. Panarin and Trouba actively looking to help him do so. PP looks incredibly dangerous.
Yet shortly after this David Quinn presumably with the support of the entire NYR organization removed him from PP1. I believe shortly after this game if not immediately after this game, I'm sure someone will call me out if that is wrong. Kakko's 2:14 PP TOI in his rookie year was
15th lowest (out of 23) of any top 2 pick in their rookie year over the last 15 drafts. Lafreniere ranked 20th on that list.
In a vacuum that decision is fine - Quinn is coaching to win. The NYR had the 7th best PP in the league in 2019-20. But the reality is that Kakko and Lafreniere have been developed differently than comparable top prospects. Most other "rebuilding" teams would leave Kakko in that role for a significant period of time after seeing the PP look so dangerous. Not doing so was part of a conscious decision by the organization to try to stay competitive by rebuilding. How can we assume this had no impact on his confidence?
That shortcut strategy to "compete while rebuilding" is looking questionable to me at the present moment. If these kids don't break through it will be proof that it is impossible to rebuild in NY, not because of impatience by the fans but because of impatience and short-sightedness by ownership.