This stuff is way more high-variance than y'all care to admit. It's like a 6 game tournament with kids that make mistakes and clutch their sticks too tight or whatever sometimes. Not everything needs to be audited backwards to determine "reasons" things happen. The first time USA ever won this thing was because of a really stupid goal, lol, and they've lost other years in equally stupid fashion. Obviously a better age group can significantly alter the percentages in your favor, but all in all, it's a weighted dice roll. They aren't playing best of sevens here.
That core group from the '21 WJC that won Gold also got beat at the Under-18s, which is a way softer tournament, and that included Jack Hughes and a team that had two straight years to build chemistry (and performed super well throughout), because Askarov stood on his head. Things happen.