You have millions of people watching superbowl, but you have billions of people watching the world cup. Why? because only americans play american football, and its only popular in USA itself. But, soccer, spread from Britian to other parts of the world, attracting people.
And, there is more commercials and timeouts in american football, because they needed advertisments to help those players earn their money. And superbowl is more of a television game, while the world cup is more wide, You listen it on the radio, you read it on the newspaper, you watch it live on TV, you watch it at the stadium itself.
Americans also want to see violence in their game, because they find yellow/red cards silly.
Soccer stars also earn more than american football stars, because they are popular EVERYWHERE
YEAH, GO AHEAD AND CALL ME TROLL, BUT SOCCER IS OBVIOUSLY BETTER