three are so many examples of players improving until they are much older and much further along in their careers than 22 and 260 games. Mackinnon, Zibanejad, Couturier, Schiefele, Stone, Reinhart to name a few
Those are the outliers, not the rule. You do understand that, right? Sure, it happens....but it isn't likely. And just using some of the players you listed:
Mackinnon- had 63 pts as a rookie and 2 other 50 point seasons by the time he turned 22.
Stone- had back to back 60 point seasons his first 2 years.
Lafreniere has never hit 40 points. Sure, he is on pace to this year, but the point remains. It is not IMPOSSIBLE he ever becomes a consistent ppg winger, but it is very unlikely.