Do you really think there is a shortage of workers in ANY field these days? How can you explain H-1B, L-1, OPT workers, etc have always come overwhelmingly from the low wage countries such as India( forget higher wage Japan or Western Europe). Heck, there are credible reports of US workers being forced to train their replacements.
I suggest you go to utube and search for the five minute "Cohen and Grigsby" video where immigration lawyers tell how to AVOID hiring qualifies Americans. There is NO labor shortage in anything these days. Instead immigration today is mostly about cheap indentured labor. And if there is such a labor shortage why do hardly any companies offer training and development these days? They used to try to develop