The US probably has one of the best child support systems in place. Not only are the child support payments realistic, there are also excellent deferring penalties for those who don't abide, as well as excellent mechanisms to collect child support arrears.
In many other countries in the world, especially in developing countries, child support systems are a joke. Either they don't have one or the system is so poorly developed that it does not serve its purpose.
My parents divorced in another country when I was 15 and my father was required to pay child support to my mother who had my custody. But the amount was absolutely ridiculous. The payment did not even cover my monthly transportation costs to school. And this was despite the fact that my father made at least twice as much as my mother. The payments stopped altogether when I was 18 even though I went on to college and experienced great financial difficulties throughout.
I think we need to be grateful that we live in a country where the rights of minors are protected and defended so well by our legal system.