In a similar vein, the Wall St Journal ran an interesting article (didn't post it, pay site) on the CPA shortage that's developed over the past few years. Among the points, some usage was being made of CPAs from India, particularly outsourcing, but more importantly the number of college accounting majors has tripled over the last 5 years. The market will solve the shortage. But only if allowed to. Another problem with H1-Bs which the article allude to is that if generously available, they essentially define compensation in a particular industry to entry level status.
I have to chime in with a first-hand observation. Physicians come to the US on H1B visa's from a number of nations. One whom I know immigrated from the Philippines and obtained a job at a clinic run by another immigrant Phillipino physician. The clinic owner requires the new immigrant physician to pay back a cash fee of many thousands of dollars for the privilege of working for him. This reduces her salary greatly but if she alerts the US government, she is afraid that she will be deported because she has signed papers saying she will not work for less than the prevailing wage in her profession. The responsibility is on her and she will put up with the cash payback so she can remain employed in the US. I was told this is not a unique occurrence.
I have also noted recently that some physician clinics have raised their "partnership buy-in" fees from nothing or a few thousand dollars to hundreds of thousands of dollars. I spoke with another immigrant physician (probably on H1B but not confirmed) who is in this position and looking for another job. I don't know if the intent is to exploit immigrants but it in effect greatly reduces the salary paid to young physicians in their first few years of practics, many of whom are immigrants but all of whom make a large salary only for tax purposes and in effect must change jobs (and face the same situation again) or pay back a big percentage of the salary they are paid.