Olympics is not just track and field. There's a whole bunch of other sports.
I see where you're coming from though. I think the two trips would be vastly different experiences indeed and both more than worth it. It would be great to see the Superbowl but there's just something about the Olympics that makes it so much more exciting. Probably the fact that I don't live in America
The Olympics is more about atmosphere than anything else. It's about walking around, finding people from your own country, banding together and supporting the hell outta the athletes representing you. It's a great way to meet heaps of people from all over the world and have an awesome time while doing it. And because it happens only once every four years the athletes take the events more seriously.
That was my biggest dissapointment watching professional live US sporting teams - the guys just didn't seem to care
(it was regular season but I still think they should've put forth a little more effort)