The Superbowl is the largest, most meaningful, and most sought-after football game, is it the 'best' game? With the best history? Thats seriously debatable
similarly, is the world cup the largest sports tournament? yes. Is it the most 'important' yeah, because its country vs country.
That said, the tournament itself is quite lame. there is no such thing as a cinderella, its brazil or germany or italy every single year. Out of 100+ countries, 3 countries have 65% of all championships. That makes for a very predictable and lame tournament.
Don't get me wrong, I love the world cup, but not because of the format