Most Americans don't watch the Tour d' France either or even the Amgen tour d' California, because even though almost everyone has ridden a bike at one time or another, most do not do so now...
About the only sports Americans watch with any interest are Baseball, Football and a bit of round ball... other than that... nothing. Even World Cup Soccer doesn't tend to draw huge crowds.
I think Budweiser has sponsor something before Americans even know it exists. We had Thunderboat racing this last weekend here in Mission Bay... loud and with beer sponsors... I'd be willing to bet the number of on site spectators was close to that of AC.