Back then and in most Olympic games, they do not line up each team and play their national anthems before each game, they only do it at the medal ceremony, so it’s an apples to oranges comparison, except that of the 30 teams at the World Cup, only ONE is acting this way.
Go back and find a full clip of the start-to-finish ABC coverage of the “Miracle on Ice” game. I can’t post a link from this phone, but the first YouTube clip I found started with the USA and USSR teams lined up on their respective blue lines for the national anthems.