It would be interesting to know how many H1b visa holders are employed in STEM positions at institutions that are exempt from the cap. What if it were something scandalous like 800,000 or 1,000,000?
If the numbers were this high, it might have something to do with the fact that there's so much double speak about STEM shortage / STEM surplus in the United States. More American STEM degree holders might be able to find jobs if they weren't forced to compete with foreign nationals.