Charles, do you assume that every US graduate with a STEM degree finds a job? Not true. Alas, companies like IBM, GE, and others have shifted and continue to shift development work to locations outside the United States. I believe 70% of GE and IBM employees live outside the US. Perhaps some of them were born in America, but obviously not the majority.
I view the wild creativity of the United States into a before and after "iron curtain". Before - the fruits of the creators stayed in the United States, and Americans developed and built the products created here. Today we are obviously on the other side of this "iron curtain". For example, in 2006 Cessna shifted an airplane parts production factory to Mexico, now 10x. the space.