People are acting like the book has been written but he's still only a teen. So much can still happen - I'll use the couturier analogy again but it was literally back and forth between "what am amazing prospect" to "what a disappointment" to "wow he's gonna be good" to "middle 6 C upside" for years until he found his groove.
Basically anyone who thinks they "know" what kind of player he will be at 25 is just naive, so many players who are better become average, and many who are worse become stars, and the trend isn't always in one direction, just because he isn't what people expected 2 years ago doesn't mean he still can't work and improve enough to be a great player.
People shouting I told you so, could be on the other end in another couple years time, like they were with couturier and so many others. They could be right as well, but only time will tell. Not every player, in fact almost all, are nowhere near finished products at 18/19