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.
I completely agree. Can you imagine what a NFL game would be like if it had some of the “flow” that a soccer game has? Best sport on the planet, hands down (except maybe professional biathlon).