In spite of all the downsides, the PhD programs do offer a lot to non-US students who want to gain legal entry into the United States. This can be the first st

In spite of all the downsides, the PhD programs do offer a lot to non-US students who want to gain legal entry into the United States. This can be the first step in the long path to a green card, which is worth a great deal of money. The equation changes for US citizens and permanent residents, because the green card and/or legal right to reside in the US isn't part of the equation. Residency + a 35K/yr post-doc is a lot more appealing if you don't already have the residency. It would be interesting to see what would happen if foreign scholars were directly awarded a 10 year residency visa and a spot on the green card list upon arrival in the US, independent of whether they remained in the Ph.D program. In other words, what would happen if the US said "you're obviously smart enough to make the best use of your own life - welcome to America, and feel free to follow your own path in life." I wouldn't be surprised if the drop-out rate increased dramatically, since the foreign students would now be free to join startups or pursue other degree paths.