> We take a 23yo Chinese engineering graduate as he's going to begin peak productivity - the USA didn't have to invest in his k-12, scholarship his university, clean the water he drank for 24 years, etc. Instantaneous social profit.

That's only the half of it. The US gives out far more F-1 student visas than H-1Bs (roughly 3x). That means that US infrastructure trains the student, but then the US doesn't get to take advantage of his or her output. Its really a lose-lose for the US.