In the 2019 WJC, Lafreniere got 8:15 of ice time on average, his highest 14-0 game was against Denmark, where he got 14:14, but went scoreless.
In 2020 WJC, Byfield got 8:41 of ice time on average, his highest being the 6-0 Loss against Russia at 12:56. If you want to find his weaknesses,
watch highlights of that game. On goal #3 and #6, there is lack of defensive awareness. He needed to put more defensive pressure on the open centerman/goal scorer. Notably, he also played 11:40 in the 4-3 win against USA, where he was a +2 against a stacked Team USA.
WJC 2020 Byfield is only
53 days (less than 2 months) older than 2019 WJC Lafreniere. Their ages and performances are very similar. He did not have a disappointing WJC if you factor that in. Im putting my money that he has a dominate WJC next year, if he is there.
Also remember, Quinton Byfield was considered a contender for #1 overall up all the until that gold game for Canada, where Lafreniere really dominated. But to compare 2020 Lafreniere to 2020 Byfield is not fair, considering Lafreniere is
312 days (or about 10 months) older than Byfield.
Aatu Raty (top tier 2021 prospect) played for Finland and had 3 points. He is only
34 days younger than Byfield, got more ice time, and no one considered his performance bad.