The interesting thing is the "conversion rate" of US Citizen undergrads to US Citizen grad-students. It's extraordinarily low.
And here's the dirty secret: the best known explanation is that it's economically irrational for a US Citizen to get a graduate/PhD degree in a STEM subject.
Agreed. I talked to Philip a few years ago before I applied to grad. school. On the other hand, I had done an undergrad in EE from an average school in India, it made incredible economic sense for me to come to the U.S. to study C.S/Math. If I had studied those things in my undergrad, I wouldn't have gone to grad. school for sure.