Agreed. Apart from understanding logic, complex math is such a small part of development. I would say programming requires the overlap of knack for math and a pure creative interest like painting. That's much, much rarer.

During the dot boom, there were plenty of CS grads, but after the dot bomb and the market dried up, people lost interest. Also, the pay and incentives aren't nearly as good as they were during the dot boom.

Add off shoring, constantly pushing down wages, and the fact that most US businesses make programming miserable, that's probably most of the big picture.