Scheifele took off in his 4th year. This is Laine's 4th year.
Yes, Scheifele is kind of prototype player here, as he was not only good starting at 21-year-old, but hit PPG and his prime as 23-year-old, on his 6th season. On average, forwards tend to hit their prime roughly at 23 years old, stay there roughly 5-6 seasons.
Laine was fully aware of that at 18-year-old, and he said it will take several years of development for him, and if I remember it correctly, he said 5 years, which would match that 23-year-old perfectly.
They also had a multi year plan to turn that ridiculously thin stick man/boy into a beast, and while they still aren't quite there, he has taken tremendous steps. My brother said before his rookie season that Laine definitely should not play NHL 16-17, since he just do not have the muscles to cope up with grown up adults. He was correct about his muscles, but Laine was able to outsmart his opponents even on NHL level, and that made him effective even before his "beast mode" could be activated due to him being very raw on physical department.
So just fasten the seatbelts firmly when season 21-22 starts and enjoy the ride