Cheap PhDs are what US business wants. And importing captive, desperate 3rd worlders on student visas is how it gets it.

https://www.nature.com/articles/d41586-018-07479-7?fbclid=IwAR2-mQbNvXYZLa_pdEmgwNVYhaTXxBrxIQ7qjhXvWU9ov_JP7VMEv8ZRNGM

A survey reveals some lab heads are using the need for visas to create unacceptable conditions for junior researchers.