Honestly, after thinking about it, the whole idol culture in Japan is not too different from any other similar phenomenon the US. Sports, politics, religion, etc. The main difference is that those are considered socially acceptable by many people and the idol culture is not. I mean a bunch of old men yelling and screaming and spending thousands of dollars on young guys running around with a ball on a field isn't too different than if you substitute the young men and a ball with young women and singing/dancing.
Except the 10 year old stuff though. In the immortal words of Walter Sobchak, "10 year olds, dude." But even in the US you have the creepy pageant show culture and there are also the parents of kids in youth sports leagues who go crazy over that stuff.