This article on adoption statistics in the United States was eye-opening. 600,000 women seek to adopt children every year. There are 129,000 children in foster care waiting to be adopted; yet only 8,000 children are actually adopted. The usual rationales don't add up: there are 12.5 prospective parents for each black child in adoptive care, six prospective parents for every child older than 13 and nearly as many for foster children with disabilities.
Thinking about all the adoptive children among my friends, there is one child who was adopted when his teenage mother gave him up on birth. Another child (9 years old) was adopted after he came to the family as a foster child. The remaining adopted children (more than a dozen) in my circle of friends were all internationally adopted. Yet, statistically, only 19,000 children are adopted internationally each year: the bureaucracy involved with international adoptions is too expensive for most parents. This kind of thing never ceases to surprise -- for an average American, only 1 out of 4 of this closest friends graduated from college -- yet, I am sure (if you are reading this on the Internets) that the vast majority of your friends did graduate from college. So, yes, few American prospective parents can afford an international adoption.
Bottom line: adoption is another market failure in America -- there are all these children in foster care, and all these parents willing to adopt them. Yet, these adoptions don't happen. The article proposes that government bureaucracies are so focused on keeping the bad parents out that they fail to provide a smooth path to the good prospective parents they should be adopting. That may be true, but there is another reason that is probably acknowledged more in private: one over-riding concern of parents who adopt stateside is that the biological parents would come back years later and sue to get the children back. Since it's much harder to do so across international borders, parents who can afford it go outside the country. And since most families adopt only one child or two, they're willing to shoulder the additional cost as insurance. So, perhaps, a better legal framework to protect the rights of adoptive parents would help.