Then why isn't the rest of the world just as enamored by American Football as Americans? It's an almost non existent sport anywhere outside the US. If it really were more fun to watch than soccer or rugby, it would surely be more fun to watch in the UK, Germany, Brazil, etc.
It's only more fun to watch because you're used to it and your sporting culture is built around it.
Soccer, god rot its socks, is probably a better model. Hours of furious sprinting and jogging, lots of posturing and almost nobody ever wins convincingly.
I have never been to war, but I have friends who have, and your description of gridiron sounds just like their description of war. 2 month faffing around at base, 2 hours all out mayhem and intense fire fights, repeat for 12 month.