It’s hilarious, really: “I know nothing about the sport except that it’s hard, some of the Team USA members have funny names, it’s so boring to watch that I must come here to tell you, I have an enlarged prostate, and you are a lib.”
Yardage was gained or lost, a first down was made or not made.
So even when it takes the ball 10 minutes to make it to the red zone before it's turned over and no points are scored, it's more exciting because of the buildup and discreteness than the soccer ball changing hands thirty times and crossing the field twenty times in the same space of time.
Also each play is a mechanical diagram that can be picked apart.