It turns out that some folks actually prefer to watch the beautiful game than play
Uncharted 2 multiplayer as evidenced by these charts Naughty Dog
posted to their blog today (and that I've summarized below). What's interesting is that the drop off in user is less than 30% of the population of people playing the sport which indicates to me that most gamers really don't care much for soccer.
As something of a data nerd I would love to see the data broken out across countries and regions but this is a pretty good start.