Why does there need to be a route for them to bring in foreign nationals?
Because in certain areas like engineering, science and medicine, there are often shortages of qualified applicants in the pool comprised of citizens and permanent residents. It took me about 7 months to fill an entry level civil engineer position (with an MS), and about 13 months to fill a mid-level civil engineer position (MS and 10-12 years of experience in the transportation design business) in Columbia, SC, despite offering very competitive wages for these positions. We are still looking for a senior project manager in Columbia or Charleston (20 to 25 years and strong relationships with the clients we work for), and it has been over a year. For every mediocre or unqualified US national who did apply for these positions, I typically had 2 to 3 better qualified foreign applicants who had an advanced degree from a highly ranked US university. Unfortunately, my firm no longer hires junior staff who need visa sponsorship because the process is tedious and expensive. The transportation design business has been booming in the southeast for the last 2+ years, and we are literally turning down work because we do not have the resources to deliver all the work we could book.
Anecdotally, my second in command was born and raised in India; I hired him about 14 years ago when he graduated from UC Berkeley with a PhD in structural design, and in this relatively short period he has become one of the most prolific Senior PMs in the company. In 2 to 3 years he will be taking over my group of about 440 people, and will become the youngest Service Line Leader and Senior VP in the company. A prime example of why US companies need to have the ability to hire the best and brightest people in the world, even if they were not born in the US.