I remember hearing that one potential reason for it not being as popular in the US was that TV stations couldn’t make as much money since theres no timeouts or stopages in play. American football has a lot more down time allowing for more ads.

Personally I think American football is boring as shit. Its one 5sec play followed by 30sec of standing around. Average game is something like 3hrs, but theres only about 10min where the ball is actually in play.