The first video is something I actually wrote a paper on while at university. Essentially Americans marketed (USA)Football better.
Anyway, it's because both Soccer and Football allow for one to identify with nationalism. Look at football clubs(soccer) such as Celtic FC, that is highly identifiable with being Irish. Many of my Irish-American friends have their jerseys.
As for American Sports, while that's a whole different issue. People are fooled to exert nationalism on jewish owned teams which are named after animals.