American sports have so many stoppages because Americans - not being the brightest of people - only have a short attention span and can't concentrate for anymore than 10 seconds at a time! Just Playin'
In my opinion, American Football has been completely manufactuared fot TV. Lots of stoppages = lots of adverts = lots of money. The Superbowl is hyped up to ridiculous proportions also.
Don't get me wrong I love all the American sports. None of them touch football though, peoples passion for it can attest to that. (If you need proof, I suggest you find your way to Glasgow on Sunday.)